diff --git a/Tests/CheckFortran.cmake b/Tests/CheckFortran.cmake
index cf47576b2..8adcafcf8 100644
--- a/Tests/CheckFortran.cmake
+++ b/Tests/CheckFortran.cmake
@@ -15,11 +15,14 @@
 if(NOT DEFINED CMAKE_Fortran_COMPILER)
   set(_desc "Looking for a Fortran compiler")
   message(STATUS ${_desc})
+  file(REMOVE_RECURSE ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/CheckFortran)
   file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/CheckFortran/CMakeLists.txt"
     "cmake_minimum_required(VERSION 2.4)
 project(CheckFortran Fortran)
 file(WRITE \"\${CMAKE_CURRENT_BINARY_DIR}/result.cmake\"
-  \"set(CMAKE_Fortran_COMPILER \\\"\${CMAKE_Fortran_COMPILER}\\\")\\n\")
+  \"set(CMAKE_Fortran_COMPILER \\\"\${CMAKE_Fortran_COMPILER}\\\")\\n\"
+  \"set(CMAKE_Fortran_FLAGS \\\"\${CMAKE_Fortran_FLAGS}\\\")\\n\"
+  )
 ")
   execute_process(
     WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/CheckFortran
@@ -42,4 +45,6 @@ file(WRITE \"\${CMAKE_CURRENT_BINARY_DIR}/result.cmake\"
   message(STATUS "${_desc} - ${CMAKE_Fortran_COMPILER}")
   set(CMAKE_Fortran_COMPILER "${CMAKE_Fortran_COMPILER}" CACHE FILEPATH "Fortran compiler")
   mark_as_advanced(CMAKE_Fortran_COMPILER)
+  set(CMAKE_Fortran_FLAGS "${CMAKE_Fortran_FLAGS}" CACHE STRING "Fortran flags")
+  mark_as_advanced(CMAKE_Fortran_FLAGS)
 endif()
diff --git a/Tests/FortranC/CMakeLists.txt b/Tests/FortranC/CMakeLists.txt
index 12d416512..f33558397 100644
--- a/Tests/FortranC/CMakeLists.txt
+++ b/Tests/FortranC/CMakeLists.txt
@@ -14,11 +14,11 @@ file(REMOVE_RECURSE ${CMAKE_BINARY_DIR}/CMakeFiles/FortranCInterface)
 if(FortranC_TEST_FLAGS)
   # Test whether FortranCInterface checks see C flags.
   set(ENV{TEST_OPT_CC} "--test-opt-cc=1")
-  set(CMAKE_C_FLAGS "$ENV{TEST_OPT_CC}")
+  set(CMAKE_C_FLAGS "$ENV{TEST_OPT_CC} ${CMAKE_C_FLAGS}")
 
   # Test whether FortranCInterface checks see Fortran flags.
   set(ENV{TEST_OPT_FC} "--test-opt-fc=1")
-  set(CMAKE_Fortran_FLAGS "$ENV{TEST_OPT_FC}")
+  set(CMAKE_Fortran_FLAGS "$ENV{TEST_OPT_FC} ${CMAKE_Fortran_FLAGS}")
 endif()
 
 include(FortranCInterface)
diff --git a/Tests/FortranC/Flags.cmake.in b/Tests/FortranC/Flags.cmake.in
index 8bf0c5cad..0b82f0ead 100644
--- a/Tests/FortranC/Flags.cmake.in
+++ b/Tests/FortranC/Flags.cmake.in
@@ -12,15 +12,14 @@ configure_file("${src}/test_opt.sh.in" "${bld}/fc.sh" @ONLY)
 set(ID)
 set(COMMAND)
 
-set(ENV{CFLAGS})
-set(ENV{FFLAGS})
-
 execute_process(
   WORKING_DIRECTORY "${bld}"
   COMMAND ${CMAKE_COMMAND} "${src}" -G "@CMAKE_TEST_GENERATOR@"
                            "-DFortranC_TEST_FLAGS=1"
                            "-DCMAKE_C_COMPILER=${bld}/cc.sh"
+                           "-DCMAKE_C_FLAGS:STRING=@CMAKE_C_FLAGS@"
                            "-DCMAKE_Fortran_COMPILER=${bld}/fc.sh"
+                           "-DCMAKE_Fortran_FLAGS:STRING=@CMAKE_Fortran_FLAGS@"
   RESULT_VARIABLE result
   )