diff --git a/src/mcp/client/sse.py b/src/mcp/client/sse.py
index 4f6241a7..b2fbc33d 100644
--- a/src/mcp/client/sse.py
+++ b/src/mcp/client/sse.py
@@ -61,7 +61,9 @@ async def sse_reader(
                                 logger.debug(f"Received SSE event: {sse.event}")
                                 match sse.event:
                                     case "endpoint":
-                                        endpoint_url = urljoin(url, sse.data)
+                                        uri_base = url.rsplit("/sse", 1)[0]
+                                        endpoint_url = urljoin(uri_base + "/", 
+                                                               sse.data.lstrip("/"))
                                         logger.info(
                                             f"Received endpoint URL: {endpoint_url}"
                                         )