diff --git a/sim.c b/sim.c
index 151b04c..85abdf4 100644
--- a/sim.c
+++ b/sim.c
@@ -2,7 +2,14 @@
 #include <stdlib.h>
 #include "fec.h"
 
-#define	MAX_RANDOM	0x7fffffff
+#ifdef _WIN32
+/* MinGW's C runtime provides rand(), but not the POSIX random(). */
+#define fec_random rand
+#define MAX_RANDOM RAND_MAX
+#else
+#define fec_random random
+#define MAX_RANDOM 0x7fffffff
+#endif
 
 /* Generate gaussian random double with specified mean and std_dev */
 double normal_rand(double mean, double std_dev)
@@ -20,8 +27,8 @@ double normal_rand(double mean, double std_dev)
    * that are inside the unit circle
    */
   do {
-    v1 = 2.0 * (double)random() / MAX_RANDOM - 1;
-    v2 = 2.0 * (double)random() / MAX_RANDOM - 1;
+    v1 = 2.0 * (double)fec_random() / MAX_RANDOM - 1;
+    v2 = 2.0 * (double)fec_random() / MAX_RANDOM - 1;
     rsq = v1*v1 + v2*v2;
   } while(rsq >= 1.0 || rsq == 0.0);
   fac = sqrt(-2.0*log(rsq)/rsq);