diff --git a/mex/sources/mjdgges/mjdgges.c b/mex/sources/mjdgges/mjdgges.c
index 6cef9891dc35da0dde89b8ea7f1917dd19d1ecf7..e42b8234cf9d1d96d6c8356eeceaef07c5916bc6 100644
--- a/mex/sources/mjdgges/mjdgges.c
+++ b/mex/sources/mjdgges/mjdgges.c
@@ -119,7 +119,7 @@ mexFunction(int nlhs, mxArray *plhs[],
   b = mxGetPr(prhs[1]);
 
   /* set criterium for stable eigenvalues */
-  if (nrhs == 3)
+  if (nrhs == 3 && mxGetM(prhs[2]) > 0)
     {
       criterium = *mxGetPr(prhs[2]);
     }