diff --git a/hist/hist/src/TFormula_v5.cxx b/hist/hist/src/TFormula_v5.cxx
index 9204314c3ea9f..7eea2c3095427 100644
--- a/hist/hist/src/TFormula_v5.cxx
+++ b/hist/hist/src/TFormula_v5.cxx
@@ -9,7 +9,7 @@
  * For the list of contributors see $ROOTSYS/README/CREDITS.             *
  *************************************************************************/
 
-#include <math.h>
+#include <cmath>
 
 #include "Riostream.h"
 #include "TROOT.h"