diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8b85f4c9b0c..f389f2b343d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,17 @@
 cmake_minimum_required(VERSION 3.14)
 
+#
+# Prevent in-source builds
+#
+if (CMAKE_BINARY_DIR STREQUAL CMAKE_SOURCE_DIR)
+   message(FATAL_ERROR
+      "\nin-source builds are not allowed: "
+      "build directory cannot be in the source directory path!\n"
+      "You MUST remove the file ${CMAKE_BINARY_DIR}/CMakeCache.txt and "
+      " the directory ${CMAKE_BINARY_DIR}/CMakeFiles/ to be able to build again.")
+endif ()
+
+
 ########################################################################
 #
 # Set variables for AMReX versioning