diff --git a/eo/src/eoPop.h b/eo/src/eoPop.h
index 068498aa..9220e3c6 100644
--- a/eo/src/eoPop.h
+++ b/eo/src/eoPop.h
@@ -38,6 +38,7 @@ Authors:
 #include <iostream>
 #include <iterator> // needed for GCC 3.2
 #include <vector>
+#include <assert.h>
 
 // EO includes
 #include <eoOp.h> // for eoInit