diff --git a/ChangeLog b/ChangeLog
index ee4d82ec7..2cbadf9e9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2012-01-11  Robert Larice
+ * src/include/ngspice/missing_math.h :
+  wrap isnan declaration, isnan is a macro on modern systems
+
 2012-01-11  Robert Larice
  * src/frontend/resource.c :
   fix printf/scanf format strings to match `unsigned long long' arguments
diff --git a/src/include/ngspice/missing_math.h b/src/include/ngspice/missing_math.h
index 0ab551e47..be4d59894 100644
--- a/src/include/ngspice/missing_math.h
+++ b/src/include/ngspice/missing_math.h
@@ -26,7 +26,7 @@ extern double scalbn(double, int);
 #endif
 
 #if !HAVE_DECL_ISNAN
-#ifndef HAVE_ISNAN
+#if !defined(HAVE_ISNAN) && !defined(isnan)
 extern int isnan(double);
 #endif
 #endif