diff --git a/Cantera/src/equil/BasisOptimize.cpp b/Cantera/src/equil/BasisOptimize.cpp
index 4b3b097fd..42b88afdd 100644
--- a/Cantera/src/equil/BasisOptimize.cpp
+++ b/Cantera/src/equil/BasisOptimize.cpp
@@ -12,6 +12,8 @@
 #include "ThermoPhase.h"
 #include "MultiPhase.h"
 
+#include <string.h>
+
 using namespace Cantera;
 using namespace std;
 
diff --git a/Cantera/src/equil/vcs_util.cpp b/Cantera/src/equil/vcs_util.cpp
index 4515b6ed8..c35493e66 100644
--- a/Cantera/src/equil/vcs_util.cpp
+++ b/Cantera/src/equil/vcs_util.cpp
@@ -15,6 +15,7 @@
 #include <cassert>
 
 #include "vcs_internal.h" 
+#include <string.h>
 
 using namespace std;