diff --git a/socketio/asyncio_server.py b/socketio/asyncio_server.py
index dcb4307..09cd5d2 100644
--- a/socketio/asyncio_server.py
+++ b/socketio/asyncio_server.py
@@ -209,6 +209,8 @@ class AsyncServer(server.Server):
 
         Note 2: this method is a coroutine.
         """
+        if to is None and sid is None:
+            raise ValueError('Cannot use call() to broadcast.')
         if not self.async_handlers:
             raise RuntimeError(
                 'Cannot use call() when async_handlers is False.')
diff --git a/socketio/server.py b/socketio/server.py
index 2af55c5..8c31707 100644
--- a/socketio/server.py
+++ b/socketio/server.py
@@ -365,6 +365,8 @@ class Server(object):
         standard concurrency solutions (such as a Lock object) to prevent this
         situation.
         """
+        if to is None and sid is None:
+            raise ValueError('Cannot use call() to broadcast.')
         if not self.async_handlers:
             raise RuntimeError(
                 'Cannot use call() when async_handlers is False.')
diff --git a/tests/asyncio/test_asyncio_server.py b/tests/asyncio/test_asyncio_server.py
index 5efe705..201aebe 100644
--- a/tests/asyncio/test_asyncio_server.py
+++ b/tests/asyncio/test_asyncio_server.py
@@ -146,6 +146,10 @@ class TestAsyncServer(unittest.TestCase):
         self.assertRaises(exceptions.TimeoutError, _run,
                           s.call('foo', sid='123', timeout=0.01))
 
+    def test_call_with_broadcast(self, eio):
+        s = asyncio_server.AsyncServer()
+        self.assertRaises(ValueError, _run, s.call('foo'))
+
     def test_call_without_async_handlers(self, eio):
         mgr = self._get_mock_manager()
         s = asyncio_server.AsyncServer(client_manager=mgr,
diff --git a/tests/common/test_server.py b/tests/common/test_server.py
index 70dbf57..44c9d89 100644
--- a/tests/common/test_server.py
+++ b/tests/common/test_server.py
@@ -138,6 +138,10 @@ class TestServer(unittest.TestCase):
         self.assertRaises(exceptions.TimeoutError, s.call, 'foo',
                           sid='123', timeout=12)
 
+    def test_call_with_broadcast(self, eio):
+        s = server.Server()
+        self.assertRaises(ValueError, s.call, 'foo')
+
     def test_call_without_async_handlers(self, eio):
         mgr = mock.MagicMock()
         s = server.Server(client_manager=mgr, async_handlers=False)