diff --git a/fs/procfs/fs_procfsuptime.c b/fs/procfs/fs_procfsuptime.c
index ff2167b8dea..2ea9071d6f0 100644
--- a/fs/procfs/fs_procfsuptime.c
+++ b/fs/procfs/fs_procfsuptime.c
@@ -266,9 +266,11 @@ 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);
+      linesize = snprintf(attr->line, UPTIME_LINELEN, "%7llu.%02u\n",
+                          sec, csec);
 #else
-      linesize = snprintf(attr->line, UPTIME_LINELEN, "%7lu.%02u\n", sec, csec);
+      linesize = snprintf(attr->line, UPTIME_LINELEN, "%7lu.%02u\n",
+                         (unsigned long)sec, csec);
 #endif
 
 #endif