diff --git a/io.c b/io.c
index 442bf52e40..24dacc5dd8 100644
--- a/io.c
+++ b/io.c
@@ -1158,7 +1158,6 @@ io_fflush(rb_io_t *fptr)
     rb_io_check_closed(fptr);
     if (fptr->wbuf.len == 0)
         return 0;
-    rb_io_check_closed(fptr);
     while (fptr->wbuf.len > 0 && io_flush_buffer(fptr) != 0) {
 	if (!rb_io_wait_writable(fptr->fd))
 	    return -1;