diff --git a/langfuse/_client/observe.py b/langfuse/_client/observe.py
index e37e91e99..ce4d862d5 100644
--- a/langfuse/_client/observe.py
+++ b/langfuse/_client/observe.py
@@ -1,4 +1,3 @@
-import asyncio
 import inspect
 import logging
 import os
@@ -169,7 +168,7 @@ def decorator(func: F) -> F:
                     capture_output=should_capture_output,
                     transform_to_string=transform_to_string,
                 )
-                if asyncio.iscoroutinefunction(func)
+                if inspect.iscoroutinefunction(func)
                 else self._sync_observe(
                     func,
                     name=name,
@@ -355,6 +354,14 @@ def sync_wrapper(*args, **kwargs):
                                 result,
                                 transform_to_string,
                             )
+                        elif inspect.isasyncgen(result):
+                            is_return_type_generator = True
+
+                            return self._wrap_async_generator_result(
+                                langfuse_span_or_generation,
+                                result,
+                                transform_to_string,
+                            )
 
                         langfuse_span_or_generation.update(output=result)