diff --git a/libsrc/nc3internal.c b/libsrc/nc3internal.c
index 95ef04533..9015e8f97 100644
--- a/libsrc/nc3internal.c
+++ b/libsrc/nc3internal.c
@@ -723,7 +723,7 @@ NC_check_vlens(NC3_INFO *ncp)
 	return NC_NOERR;
 
     if (fIsSet(ncp->flags,NC_64BIT_DATA)) /* CDF-5 */
-	vlen_max = (size_t)X_INT64_MAX - 3; /* "- 3" handles rounded-up size */
+	vlen_max = X_INT64_MAX - 3; /* "- 3" handles rounded-up size */
     else if (fIsSet(ncp->flags,NC_64BIT_OFFSET) && sizeof(off_t) > 4)
 	/* CDF2 format and LFS */
 	vlen_max = X_UINT_MAX - 3; /* "- 3" handles rounded-up size */