diff --git a/MAC/MACIO/test/tProtocol.cc b/MAC/MACIO/test/tProtocol.cc
index 7a7a02d713af36123ec2c1bb6c5eb881081bea1f..f873e2f60611ddb7572289ee1dcbfc976e269aaf 100644
--- a/MAC/MACIO/test/tProtocol.cc
+++ b/MAC/MACIO/test/tProtocol.cc
@@ -25,6 +25,7 @@
 
 //# Includes
 #include <Common/LofarLogger.h>
+#include <Common/StringUtil.h>
 #include "testprotocol.ph"
 #include "Echo_Protocol.ph"