diff --git a/val.py b/val.py
index 48207a1130a6..006ade37d03e 100644
--- a/val.py
+++ b/val.py
@@ -275,6 +275,8 @@ def run(
     # Print results
     pf = '%20s' + '%11i' * 2 + '%11.3g' * 4  # print format
     LOGGER.info(pf % ('all', seen, nt.sum(), mp, mr, map50, map))
+    if nt.sum() == 0:
+        LOGGER.warning(emojis(f'WARNING: no labels found in {task} set, can not compute metrics without labels ⚠️'))
 
     # Print results per class
     if (verbose or (nc < 50 and not training)) and nc > 1 and len(stats):