diff --git a/cmake/FindEigen.cmake b/cmake/FindEigen.cmake
index e785d28d..49e9172f 100644
--- a/cmake/FindEigen.cmake
+++ b/cmake/FindEigen.cmake
@@ -53,7 +53,7 @@ macro(_eigen3_check_version)
   endif(NOT EIGEN_VERSION_OK)
 endmacro(_eigen3_check_version)
 
-if (EIGEN_INCLUDE_DIRS)
+if (EIGEN_INCLUDE_DIR)
 
   # in cache already
   _eigen3_check_version()