diff --git a/reactos/tools/sysreg/conf_parser.cpp b/reactos/tools/sysreg/conf_parser.cpp
index ab87971cc4e..62818a8f269 100644
--- a/reactos/tools/sysreg/conf_parser.cpp
+++ b/reactos/tools/sysreg/conf_parser.cpp
@@ -12,6 +12,7 @@
 #include <sstream>
 #include <fstream>
 #include <cstdio>
+#include <cstdlib>
 
 namespace Sysreg_
 {