diff --git a/src/spicelib/parser/ptfuncs.c b/src/spicelib/parser/ptfuncs.c
index 41fed8606..6b23a8ebd 100644
--- a/src/spicelib/parser/ptfuncs.c
+++ b/src/spicelib/parser/ptfuncs.c
@@ -248,7 +248,7 @@ PTln(double arg)
 double
 PTlog(double arg)
 {
-    if (arg <= 0.0)
+    if (arg < 0.0)
         return (HUGE);
     return (log10(arg));
 }