diff --git a/libpwrutils/bitset.h b/libpwrutils/bitset.h
index a0a2be6f47c939cb802b99a35ffcd9888de8eda8..fa4ddc3a420613a0e4994fdb01d8295738da006d 100644
--- a/libpwrutils/bitset.h
+++ b/libpwrutils/bitset.h
@@ -6,6 +6,7 @@
 #include <bitset>
 #include <boost/functional/hash.hpp>
 #include <boost/pending/lowest_bit.hpp>
+#include <climits>
 
 
 namespace PwrNlp {