diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index bfe82fa3d8c10d..fc654883e01ca9 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -644,14 +644,14 @@ def __sleep0():
 async def sleep(delay, result=None):
     """Coroutine that completes after a given time (in seconds)."""
 
-    # check delay value is not nan
-    if math.isnan(delay):
-        raise ValueError("Invalid delay: NaN (not a number)")
-
     if delay <= 0:
         await __sleep0()
         return result
 
+    # check delay value is not nan
+    if math.isnan(delay):
+        raise ValueError("Invalid delay: NaN (not a number)")
+
     loop = events.get_running_loop()
     future = loop.create_future()
     h = loop.call_later(delay,