diff --git a/ExternalProjectDependency.cmake b/ExternalProjectDependency.cmake
index 467c6ba..8dd902a 100644
--- a/ExternalProjectDependency.cmake
+++ b/ExternalProjectDependency.cmake
@@ -1017,13 +1017,16 @@ endfunction()
 #
 #  ExternalProject_SetIfNotDefined(<var> <defaultvalue> [OBFUSCATE] [QUIET])
 #
-# The default value is set with:
-#  (1) if set, the value environment variable <var>.
-#  (2) if set, the value of local variable variable <var>.
-#  (3) if none of the above, the value passed as a parameter.
+# If *NOT* already defined, the variable <var> is set with:
+#  (1) the value of the environment variable <var>, if defined.
+#  (2) the value of the local variable variable <var>, if defined.
+#  (3) if none of the above is defined, the <defaultvalue> passed as a parameter.
 #
-# Setting the optional parameter 'OBFUSCATE' will display 'OBFUSCATED' instead of the real value.
-# Setting the optional parameter 'QUIET' will not display any message.
+# Passing the optional parameter 'OBFUSCATE' will display 'OBFUSCATED' instead of the real value.
+# Passing the optional parameter 'QUIET' will not display any message.
+#
+# For convenience, the value of the cache variable named <var> will
+# be displayed if it was set and if QUIET has not been passed.
 macro(ExternalProject_SetIfNotDefined var defaultvalue)
   set(_obfuscate FALSE)
   set(_quiet FALSE)
@@ -1055,6 +1058,14 @@ macro(ExternalProject_SetIfNotDefined var defaultvalue)
     endif()
     set(${var} "${defaultvalue}")
   endif()
+  get_property(_is_set CACHE ${var} PROPERTY VALUE SET)
+  if(_is_set AND NOT _quiet)
+    set(_value "${${var}}")
+    if(_obfuscate)
+      set(_value "OBFUSCATED")
+    endif()
+    message(STATUS "Cache variable '${var}' set to '${_value}'")
+  endif()
 endmacro()
 
 #.rst:
diff --git a/Tests/ArtichokeTestUtility.cmake b/Tests/ArtichokeTestUtility.cmake
index e8889e1..1e04528 100644
--- a/Tests/ArtichokeTestUtility.cmake
+++ b/Tests/ArtichokeTestUtility.cmake
@@ -19,6 +19,14 @@ function(check_variable var_name expected_value)
   endif()
 endfunction()
 
+function(check_env_variable var_name expected_value)
+  if(NOT "x$ENV{${var_name}}" STREQUAL "x${expected_value}")
+    message(FATAL_ERROR "CMake variable [$ENV{${var_name}}] is incorrectly set !\n"
+                        "current:$ENV{${var_name}}\n"
+                        "expected:${expected_value}")
+  endif()
+endfunction()
+
 function(configure_external_projects_for_test name)
   set(depends "${expected_${name}_DEPENDS}")
   set(indent "${ARGV1}")
diff --git a/Tests/CMakeLists.txt b/Tests/CMakeLists.txt
index 922b5b7..67ea765 100644
--- a/Tests/CMakeLists.txt
+++ b/Tests/CMakeLists.txt
@@ -85,6 +85,7 @@ set(tests_source_dir ${CMAKE_SOURCE_DIR})
 add_project_test(AddDependencies SuperBuild)
 add_project_test(AlwaysConfigure SuperBuild)
 add_project_test(ExternalProjectFileLookup SuperBuild)
+add_project_test(ExternalProject_SetIfNotDefined-Cache SuperBuild)
 add_project_test(MarkAsSuperBuild SuperBuild)
 add_project_test(MarkAsSuperBuild-EP_ARGS_VAR SuperBuild)
 add_project_test(MarkAsSuperBuild-WithNotFoundVariable SuperBuild)
diff --git a/Tests/ExternalProject_SetIfNotDefined-Cache-Test/CMakeLists.txt b/Tests/ExternalProject_SetIfNotDefined-Cache-Test/CMakeLists.txt
new file mode 100644
index 0000000..41e39e0
--- /dev/null
+++ b/Tests/ExternalProject_SetIfNotDefined-Cache-Test/CMakeLists.txt
@@ -0,0 +1,41 @@
+cmake_minimum_required(VERSION 2.8.7)
+
+if(POLICY CMP0054)
+  cmake_policy(SET CMP0054 OLD)
+endif()
+
+project(ExternalProject_SetIfNotDefined-Cache-Test NONE)
+
+set(CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/../../" ${CMAKE_MODULE_PATH})
+include(ExternalProjectDependency)
+
+include(${CMAKE_CURRENT_SOURCE_DIR}/../ArtichokeTestUtility.cmake)
+
+# prefix
+set(p "ExternalProject_SetIfNotDefined-Cache-Test")
+
+# Check that cache variable is not overridden
+set(${p}_BLUE "cache-blue" CACHE STRING "")
+check_variable(${p}_BLUE "cache-blue")
+ExternalProject_SetIfNotDefined(${p}_BLUE "default-blue")
+check_variable(${p}_BLUE "cache-blue")
+
+# Check that env variable is not overriden
+set(ENV{${p}_RED} "env-red")
+check_env_variable(${p}_RED "env-red")
+check_variable_not_defined(${p}_RED)
+ExternalProject_SetIfNotDefined(${p}_RED "default-red")
+check_variable(${p}_RED "env-red")
+
+# Check that local variable is not overriden
+set(${p}_GREEN "local-green")
+check_variable(${p}_GREEN "local-green")
+ExternalProject_SetIfNotDefined(${p}_GREEN "default-green")
+check_variable(${p}_GREEN "local-green")
+
+# Check that local variable still has precedence over cache variable
+set(${p}_CYAN "cache-cyan" CACHE STRING "")
+check_variable(${p}_CYAN "cache-cyan")
+set(${p}_CYAN "local-cyan")
+ExternalProject_SetIfNotDefined(${p}_CYAN "default-cyan")
+check_variable(${p}_CYAN "local-cyan")