diff --git a/src/decorators/is-object.spec.ts b/src/decorators/is-object.spec.ts
index 02cc83a..c7b0015 100644
--- a/src/decorators/is-object.spec.ts
+++ b/src/decorators/is-object.spec.ts
@@ -20,7 +20,7 @@ describe('IsObject', () => {
     });
 
     it('transforms objects', async () => {
-      expect(output(make(Test, { objectField: { a: 1 }, b: 2 }))).toStrictEqual({
+      expect(output(make(Test, { objectField: { a: 1 }, b: 2 } as never))).toStrictEqual({
         objectField: { a: 1 },
       });
     });
diff --git a/src/decorators/is-string.spec.ts b/src/decorators/is-string.spec.ts
index c494a54..4f06abf 100644
--- a/src/decorators/is-string.spec.ts
+++ b/src/decorators/is-string.spec.ts
@@ -88,15 +88,24 @@ describe('IsString', () => {
       );
     });
 
-    it('allows empty strings if canBeEmpty is specified', async () => {
+    it('allows empty strings if canBeEmpty is set to true', async () => {
       class TestCanBeEmpty {
         @IsString({ canBeEmpty: true, maxLength: 10 })
         stringField!: string;
       }
 
-      expect(await input(TestCanBeEmpty, { stringField: '' })).toStrictEqual(
-        Result.ok(make(TestCanBeEmpty, { stringField: '' })),
-      );
+      const res = await input(TestCanBeEmpty, { stringField: '' });
+      expect(res).toStrictEqual(Result.ok(make(TestCanBeEmpty, { stringField: '' })));
+    });
+
+    it('does not allows empty strings if canBeEmpty is set to false', async () => {
+      class TestCanNotBeEmpty {
+        @IsString({ canBeEmpty: false, maxLength: 10 })
+        stringField!: string;
+      }
+
+      const res = await input(TestCanNotBeEmpty, { stringField: '' });
+      expect(res).toStrictEqual(Result.err('stringField should not be empty'));
     });
   });
 
diff --git a/src/decorators/is-string.ts b/src/decorators/is-string.ts
index 8dbee15..657484e 100644
--- a/src/decorators/is-string.ts
+++ b/src/decorators/is-string.ts
@@ -1,6 +1,7 @@
 import {
   IsEmail,
   isISO8601,
+  IsNotEmpty,
   IsString as IsStringCV,
   Length,
   Matches,
@@ -37,7 +38,7 @@ export const IsString = ({
 }: PropertyOptions<
   string,
   {
-    canBeEmpty?: true;
+    canBeEmpty?: boolean;
     maxLength?: number;
     minLength?: number;
     pattern?: { regex: RegExp; message?: ValidationOptions['message'] };
@@ -57,7 +58,8 @@ export const IsString = ({
     },
     base,
     IsStringCV({ each: !!base.isArray }),
-    canBeEmpty || minLength !== undefined || maxLength !== undefined
+    canBeEmpty === false ? IsNotEmpty({ each: !!base.isArray }) : noop,
+    minLength !== undefined || maxLength !== undefined
       ? Length(minLength ?? 0, maxLength, { each: !!base.isArray })
       : noop,
     isEmail ? IsEmail(undefined, { each: !!base.isArray }) : noop,
diff --git a/tests/helpers.ts b/tests/helpers.ts
index 0e299e8..7cc9e4d 100644
--- a/tests/helpers.ts
+++ b/tests/helpers.ts
@@ -9,7 +9,10 @@ import { ClassConstructor, instanceToPlain, plainToClass } from 'class-transform
 import { validate, ValidationError } from 'class-validator';
 import { Result } from 'true-myth';
 
-export function make<T, D extends T>(cls: ClassConstructor<T>, object: D): D {
+export function make<C extends ClassConstructor<unknown>>(
+  cls: C,
+  object: InstanceType<C>,
+): InstanceType<C> {
   return Object.assign(new cls() as never, object);
 }