diff --git a/lib/resty/mlcache.lua b/lib/resty/mlcache.lua
index bd56ff83c..2f37fc034 100644
--- a/lib/resty/mlcache.lua
+++ b/lib/resty/mlcache.lua
@@ -22,17 +22,30 @@ local _M = {}
 local mt = { __index = _M }
 
 
-function _M.new(shm, lru_size, ttl)
+function _M.new(shm, opts)
     if type(shm) ~= "string" then
-        return error("shm must be a string", 2)
+        return error("shm must be a string")
     end
 
-    if type(lru_size) ~= "number" then
-        return error("lru_size must be a number", 2)
-    end
+    if opts then
+        if type(opts) ~= "table" then
+            return error("opts must be a table")
+        end
+
+        if opts.lru_size and type(opts.lru_size) ~= "number" then
+            return error("opts.lru_size must be a number")
+        end
 
-    if ttl and type(ttl) ~= "number" then
-        return error("ttl must be a number", 2)
+        if opts.ttl and type(opts.ttl) ~= "number" then
+            return error("opts.ttl must be a number")
+        end
+
+        if opts.neg_ttl and type(opts.neg_ttl) ~= "number" then
+            return error("opts.neg_ttl must be a number")
+        end
+
+    else
+        opts = {}
     end
 
     local dict = shared[shm]
@@ -41,10 +54,11 @@ function _M.new(shm, lru_size, ttl)
     end
 
     local ml_cache = {
-        lru        = lrucache.new(lru_size),
+        lru        = lrucache.new(opts.lru_size or 100),
         dict       = dict,
         shm        = shm,
-        ttl        = ttl or 30,
+        ttl        = opts.ttl     or 30,
+        neg_ttl    = opts.neg_ttl or 5
     }
 
     return setmetatable(ml_cache, mt)
@@ -58,7 +72,7 @@ local function set_lru(self, key, value, ttl)
 end
 
 
-local function shmlru_get(self, key, ttl)
+local function shmlru_get(self, key, ttl, neg_ttl)
     local v, err = self.dict:get(key)
     if err then
         return nil, "could not read from lua_shared_dict: " .. err
@@ -70,7 +84,7 @@ local function shmlru_get(self, key, ttl)
         end
 
         if v == CACHE_MISS_SENTINEL_SHM then
-            return set_lru(self, key, CACHE_MISS_SENTINEL_LRU, ttl)
+            return set_lru(self, key, CACHE_MISS_SENTINEL_LRU, neg_ttl)
         end
 
         -- maybe need to decode if encoded
@@ -95,18 +109,18 @@ local function shmlru_get(self, key, ttl)
 end
 
 
-local function shmlru_set(self, key, value, ttl)
+local function shmlru_set(self, key, value, ttl, neg_ttl)
     if value == nil then
         -- we need to cache that this was a miss, and ensure cache hit for a
         -- nil value
-        local ok, err = self.dict:set(key, CACHE_MISS_SENTINEL_SHM, ttl)
+        local ok, err = self.dict:set(key, CACHE_MISS_SENTINEL_SHM, neg_ttl)
         if not ok then
             return nil, "could not write to lua_shared_dict: " .. err
         end
 
         -- set our own worker's LRU cache
 
-        self.lru:set(key, CACHE_MISS_SENTINEL_LRU, ttl)
+        self.lru:set(key, CACHE_MISS_SENTINEL_LRU, neg_ttl)
 
         return nil
     end
@@ -158,26 +172,45 @@ end
 
 function _M:get(key, opts, cb, ...)
     if type(key) ~= "string" then
-        return error("key must be a string", 2)
+        return error("key must be a string")
     end
 
     if type(cb) ~= "function" then
-        return error("callback must be a function", 2)
+        return error("callback must be a function")
     end
 
+    -- opts validation
+
+    local ttl
+    local neg_ttl
+
     if opts then
         if type(opts) ~= "table" then
-            return error("opts must be a table", 2)
+            return error("opts must be a table")
         end
 
-        if type(opts.ttl) ~= "number" then
-            return error("opts.ttl must be a number", 2)
+        if opts.ttl and type(opts.ttl) ~= "number" then
+            return error("opts.ttl must be a number")
         end
 
-    else
-        opts = {}
+        if opts.neg_ttl and type(opts.neg_ttl) ~= "number" then
+            return error("opts.neg_ttl must be a number")
+        end
+
+        ttl     = opts.ttl
+        neg_ttl = opts.neg_ttl
     end
 
+    if not ttl then
+        ttl = self.ttl
+    end
+
+    if not neg_ttl then
+        neg_ttl = self.neg_ttl
+    end
+
+    -- worker LRU cache retrieval
+
     local data = self.lru:get(key)
     if data == CACHE_MISS_SENTINEL_LRU then
         return nil
@@ -189,10 +222,8 @@ function _M:get(key, opts, cb, ...)
 
     -- not in worker's LRU cache, need shm lookup
 
-    local ttl = opts.ttl or self.ttl
-
     local err
-    data, err = shmlru_get(self, key, ttl)
+    data, err = shmlru_get(self, key, ttl, neg_ttl)
     if err then
         return nil, err
     end
@@ -220,7 +251,7 @@ function _M:get(key, opts, cb, ...)
 
     -- check for another worker's success at running the callback
 
-    data = shmlru_get(self, key, ttl)
+    data = shmlru_get(self, key, ttl, neg_ttl)
     if data then
         return unlock_and_ret(lock, data)
     end
@@ -232,7 +263,7 @@ function _M:get(key, opts, cb, ...)
         return unlock_and_ret(lock, nil, "callback threw an error: " .. err)
     end
 
-    local value, err = shmlru_set(self, key, err, ttl)
+    local value, err = shmlru_set(self, key, err, ttl, neg_ttl)
     if err then
         return unlock_and_ret(lock, nil, err)
     end
diff --git a/t/01-new.t b/t/01-new.t
index abcc133fa..cc310ff7a 100644
--- a/t/01-new.t
+++ b/t/01-new.t
@@ -40,14 +40,14 @@ shm must be a string
 
 
 
-=== TEST 2: new() validates lru_size
+=== TEST 2: new() validates opts
 --- http_config eval: $::HttpConfig
 --- config
     location = /t {
         content_by_lua_block {
             local mlcache = require "resty.mlcache"
 
-            local ok, err = pcall(mlcache.new, "")
+            local ok, err = pcall(mlcache.new, "", "foo")
             if not ok then
                 ngx.log(ngx.ERR, err)
             end
@@ -58,7 +58,7 @@ GET /t
 --- response_body
 
 --- error_log
-lru_size must be a number
+opts must be a table
 
 
 
@@ -69,7 +69,7 @@ lru_size must be a number
         content_by_lua_block {
             local mlcache = require "resty.mlcache"
 
-            local cache, err = mlcache.new("foo", 200)
+            local cache, err = mlcache.new("foo")
             if not cache then
                 ngx.log(ngx.ERR, err)
             end
@@ -84,14 +84,40 @@ no such lua_shared_dict: foo
 
 
 
-=== TEST 4: new() validates ttl
+=== TEST 4: new() validates lru_size
+--- http_config eval: $::HttpConfig
+--- config
+    location = /t {
+        content_by_lua_block {
+            local mlcache = require "resty.mlcache"
+
+            local ok, err = pcall(mlcache.new, "cache", {
+                lru_size = "",
+            })
+            if not ok then
+                ngx.log(ngx.ERR, err)
+            end
+        }
+    }
+--- request
+GET /t
+--- response_body
+
+--- error_log
+lru_size must be a number
+
+
+
+=== TEST 5: new() validates ttl
 --- http_config eval: $::HttpConfig
 --- config
     location = /t {
         content_by_lua_block {
             local mlcache = require "resty.mlcache"
 
-            local ok, err = pcall(mlcache.new, "cache", 200, "")
+            local ok, err = pcall(mlcache.new, "cache", {
+                ttl = ""
+            })
             if not ok then
                 ngx.log(ngx.ERR, err)
             end
@@ -106,20 +132,45 @@ ttl must be a number
 
 
 
-=== TEST 5: new() creates an mlcache object with defaults
+=== TEST 6: new() validates neg_ttl
 --- http_config eval: $::HttpConfig
 --- config
     location = /t {
         content_by_lua_block {
             local mlcache = require "resty.mlcache"
 
-            local cache, err = mlcache.new("cache", 200)
+            local ok, err = pcall(mlcache.new, "cache", {
+                neg_ttl = ""
+            })
+            if not ok then
+                ngx.log(ngx.ERR, err)
+            end
+        }
+    }
+--- request
+GET /t
+--- response_body
+
+--- error_log
+neg_ttl must be a number
+
+
+
+=== TEST 7: new() creates an mlcache object with defaults
+--- http_config eval: $::HttpConfig
+--- config
+    location = /t {
+        content_by_lua_block {
+            local mlcache = require "resty.mlcache"
+
+            local cache, err = mlcache.new("cache")
             if not cache then
                 ngx.log(ngx.ERR, err)
             end
 
             ngx.say(type(cache))
             ngx.say(type(cache.ttl))
+            ngx.say(type(cache.neg_ttl))
         }
     }
 --- request
@@ -127,5 +178,6 @@ GET /t
 --- response_body
 table
 number
+number
 --- no_error_log
 [error]
diff --git a/t/02-get.t b/t/02-get.t
index 67a73b7c0..e569a5c9f 100644
--- a/t/02-get.t
+++ b/t/02-get.t
@@ -3,7 +3,6 @@
 use Test::Nginx::Socket::Lua;
 use Cwd qw(cwd);
 
-master_on();
 workers(2);
 
 #repeat_each(2);
@@ -28,7 +27,7 @@ __DATA__
         content_by_lua_block {
             local mlcache = require "resty.mlcache"
 
-            local cache, err = mlcache.new("cache", 200)
+            local cache, err = mlcache.new("cache")
             if not cache then
                 ngx.log(ngx.ERR, err)
                 return
@@ -42,7 +41,7 @@ __DATA__
     }
 --- request
 GET /t
---- response_body_like
+--- response_body
 key must be a string
 --- no_error_log
 [error]
@@ -56,7 +55,7 @@ key must be a string
         content_by_lua_block {
             local mlcache = require "resty.mlcache"
 
-            local cache, err = mlcache.new("cache", 200)
+            local cache, err = mlcache.new("cache")
             if not cache then
                 ngx.log(ngx.ERR, err)
                 return
@@ -70,7 +69,7 @@ key must be a string
     }
 --- request
 GET /t
---- response_body_like
+--- response_body
 callback must be a function
 --- no_error_log
 [error]
@@ -85,7 +84,7 @@ callback must be a function
         content_by_lua_block {
             local mlcache = require "resty.mlcache"
 
-            local cache, err = mlcache.new("cache", 200)
+            local cache, err = mlcache.new("cache")
             if not cache then
                 ngx.log(ngx.ERR, err)
                 return
@@ -99,7 +98,7 @@ callback must be a function
     }
 --- request
 GET /t
---- response_body_like
+--- response_body
 opts must be a table
 --- no_error_log
 [error]
@@ -113,7 +112,7 @@ opts must be a table
         content_by_lua_block {
             local mlcache = require "resty.mlcache"
 
-            local cache, err = mlcache.new("cache", 200)
+            local cache, err = mlcache.new("cache")
             if not cache then
                 ngx.log(ngx.ERR, err)
                 return
@@ -145,7 +144,7 @@ callback threw an error: .*? oops
         content_by_lua_block {
             local mlcache = require "resty.mlcache"
 
-            local cache, err = mlcache.new("cache", 200)
+            local cache, err = mlcache.new("cache")
             if not cache then
                 ngx.log(ngx.ERR, err)
                 return
@@ -182,7 +181,7 @@ number
         content_by_lua_block {
             local mlcache = require "resty.mlcache"
 
-            local cache, err = mlcache.new("cache", 200)
+            local cache, err = mlcache.new("cache")
             if not cache then
                 ngx.log(ngx.ERR, err)
                 return
@@ -219,7 +218,7 @@ false
         content_by_lua_block {
             local mlcache = require "resty.mlcache"
 
-            local cache, err = mlcache.new("cache", 200)
+            local cache, err = mlcache.new("cache")
             if not cache then
                 ngx.log(ngx.ERR, err)
                 return
@@ -256,7 +255,7 @@ nil
         content_by_lua_block {
             local mlcache = require "resty.mlcache"
 
-            local cache, err = mlcache.new("cache", 200)
+            local cache, err = mlcache.new("cache")
             if not cache then
                 ngx.log(ngx.ERR, err)
                 return
@@ -294,7 +293,7 @@ hello world
             local cjson = require "cjson"
             local mlcache = require "resty.mlcache"
 
-            local cache, err = mlcache.new("cache", 200)
+            local cache, err = mlcache.new("cache")
             if not cache then
                 ngx.log(ngx.ERR, err)
                 return
@@ -337,7 +336,7 @@ returned table: {"subt":{"foo":"bar"},"hello":"world"}
         content_by_lua_block {
             local mlcache = require "resty.mlcache"
 
-            local cache, err = mlcache.new("cache", 200)
+            local cache, err = mlcache.new("cache")
             if not cache then
                 ngx.log(ngx.ERR, err)
                 return
@@ -372,7 +371,9 @@ GET /t
         content_by_lua_block {
             local mlcache = require "resty.mlcache"
 
-            local cache, err = mlcache.new("cache", 200, 1)
+            local cache, err = mlcache.new("cache", {
+                ttl = 1
+            })
             if not cache then
                 ngx.log(ngx.ERR, err)
                 return
@@ -424,14 +425,17 @@ in callback
 
 
 
-=== TEST 12: get() caches miss (nil) for 'ttl'
+=== TEST 12: get() caches miss (nil) for 'neg_ttl'
 --- http_config eval: $::HttpConfig
 --- config
     location = /t {
         content_by_lua_block {
             local mlcache = require "resty.mlcache"
 
-            local cache, err = mlcache.new("cache", 200, 1)
+            local cache, err = mlcache.new("cache", {
+                ttl     = 10,
+                neg_ttl = 1
+            })
             if not cache then
                 ngx.log(ngx.ERR, err)
                 return
@@ -488,7 +492,7 @@ in callback
         content_by_lua_block {
             local mlcache = require "resty.mlcache"
 
-            local cache, err = mlcache.new("cache", 200, 1)
+            local cache, err = mlcache.new("cache")
             if not cache then
                 ngx.log(ngx.ERR, err)
                 return