diff --git a/CMakeLists.txt b/CMakeLists.txt
index 49857eee4..22c1f00a5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -622,7 +622,7 @@ execute_process(COMMAND ${PYTHON_EXECUTABLE} -c "import os; os.environ['DISTUTIL
 
 if(PYTHON_NUMPY_PROCESS EQUAL 0)
     set(PYTHON_USE_NUMPY 1)
-    add_definitions(-D PYTHON_USE_NUMPY=1)
+    add_definitions(-DPYTHON_USE_NUMPY=1)
     include_directories(AFTER ${PYTHON_NUMPY_INCLUDE_DIRS})
     message(STATUS "    Use NumPy headers from: ${PYTHON_NUMPY_INCLUDE_DIRS}")
 else()