diff --git a/src/indent.c b/src/indent.c
index b62308d..9b137b0 100644
--- a/src/indent.c
+++ b/src/indent.c
@@ -71,7 +71,7 @@
 	int n = atoi((char *)cp);
 
 	// Catch negative values, overflow and ridiculous big values.
-	if (n < 0 || n > TABSTOP_MAX)
+	if (n <= 0 || n > TABSTOP_MAX)
 	{
 	    semsg(_(e_invalid_argument_str), cp);
 	    vim_free(*array);