diff --git a/taskflow/utils/async_utils.py b/taskflow/utils/async_utils.py
index 0599870d..6d280dfe 100644
--- a/taskflow/utils/async_utils.py
+++ b/taskflow/utils/async_utils.py
@@ -22,16 +22,25 @@ from taskflow.utils import eventlet_utils as eu
 def wait_for_any(fs, timeout=None):
     """Wait for one of the futures to complete.
 
-    Works correctly with both green and non-green futures.
+    Works correctly with both green and non-green futures (but not both
+    together, since this can't be guaranteed to avoid dead-lock due to how
+    the waiting implementations are different when green threads are being
+    used).
 
-    Returns pair (done, not_done).
+    Returns pair (done futures, not done futures).
     """
-    any_green = any(isinstance(f, eu.GreenFuture) for f in fs)
-    if any_green:
-        return eu.wait_for_any(fs, timeout=timeout)
-    else:
+    green_fs = sum(1 for f in fs if isinstance(f, eu.GreenFuture))
+    if not green_fs:
         return tuple(futures.wait(fs, timeout=timeout,
                                   return_when=futures.FIRST_COMPLETED))
+    else:
+        non_green_fs = len(fs) - green_fs
+        if non_green_fs:
+            raise RuntimeError("Can not wait on %s green futures and %s"
+                               " non-green futures in the same `wait_for_any`"
+                               " call" % (green_fs, non_green_fs))
+        else:
+            return eu.wait_for_any(fs, timeout=timeout)
 
 
 def make_completed_future(result):