diff --git a/fs/procfs/fs_procfsuptime.c b/fs/procfs/fs_procfsuptime.c
index f9e76cb897..c39ade3407 100644
--- a/fs/procfs/fs_procfsuptime.c
+++ b/fs/procfs/fs_procfsuptime.c
@@ -265,7 +265,11 @@ static ssize_t uptime_read(FAR struct file *filep, FAR char *buffer,
 
       /* Convert the seconds + hundredths of seconds to a string */
 
+#ifdef CONFIG_SYSTEM_TIME64
+      linesize = snprintf(attr->line, UPTIME_LINELEN, "%7llu.%02u\n", sec, csec);
+#else
       linesize = snprintf(attr->line, UPTIME_LINELEN, "%7lu.%02u\n", sec, csec);
+#endif
 
 #endif
       /* Save the linesize in case we are re-entered with f_pos > 0 */