diff --git a/MathLib/CMakeLists.txt b/MathLib/CMakeLists.txt
index 763b6aabc5bc1b5f4326651484007fc579e3122f..5d6f80476af78859c1542306ba4a50fd468f584d 100644
--- a/MathLib/CMakeLists.txt
+++ b/MathLib/CMakeLists.txt
@@ -61,5 +61,5 @@ target_compile_definitions(MathLib
     $<$<BOOL:${OGS_USE_EIGEN}>:OGS_USE_EIGEN>
     $<$<BOOL:${CVODE_FOUND}>:CVODE_FOUND>
     PRIVATE
-    $<$<BOOL:${USE_MKL}>:USE_MKL>
+    $<$<BOOL:${OGS_USE_MKL}>:USE_MKL>
 )