diff --git a/mex/cmake/FindELTOPO.cmake b/mex/cmake/FindELTOPO.cmake
index 6606bc53..d392c3e0 100644
--- a/mex/cmake/FindELTOPO.cmake
+++ b/mex/cmake/FindELTOPO.cmake
@@ -19,7 +19,9 @@ FIND_PATH(LIBELTOPO_INCLUDE_DIR eltopo.h
 # Includes must be found
 if(NOT LIBELTOPO_INCLUDE_DIR)
   set(LIBELTOPO_INCLUDE_DIR FALSE)
-  message(FATAL_ERROR "could NOT find LIBELTOPO_INCLUDE_DIR")
+  if(LIBELTOPO_FIND_REQUIRED)
+    message(FATAL_ERROR "could NOT find LIBELTOPO_INCLUDE_DIR")
+  endif(LIBELTOPO_FIND_REQUIRED)
 endif(NOT LIBELTOPO_INCLUDE_DIR)
 
 if(LIBELTOPO_INCLUDE_DIR)
@@ -32,7 +34,9 @@ FIND_LIBRARY(LIBELTOPO_LIBRARY NAME eltopo_release PATHS ${LIBELTOPO_INCLUDE_DIR
 # Main library must be found
 if(NOT LIBELTOPO_LIBRARY)
   set(LIBELTOPO_FOUND FALSE)
-  message(FATAL_ERROR "could NOT find LIBELTOPO")
+  if(LIBELTOPO_FIND_REQUIRED)
+    message(FATAL_ERROR "could NOT find LIBELTOPO")
+  endif(LIBELTOPO_FIND_REQUIRED)
 endif(NOT LIBELTOPO_LIBRARY)