diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index e8b1361dbb40bfb23a22dfb79ee53993706f1248..24c55d2d239b39d00ae36f433017d2f5daf269d2 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -9,7 +9,7 @@ configure_file(
 add_library(fortran-support
   mo_exception.f90
   mo_expression.f90
-  mo_lib_fortran_tools.f90
+  mo_lib_fortran_tools.F90
   mo_hash_table.f90
   mo_io_units.f90
   mo_namelist.f90