diff --git a/mex/sources/mjdgges/mjdgges.c b/mex/sources/mjdgges/mjdgges.c
index bbd91a40c..2237ce292 100644
--- a/mex/sources/mjdgges/mjdgges.c
+++ b/mex/sources/mjdgges/mjdgges.c
@@ -18,6 +18,7 @@
  */
 
 #include <string.h>
+#include <math.h>
 
 #include <dynmex.h>
 #include <dynlapack.h>