diff --git a/src/replit_river/client_session.py b/src/replit_river/client_session.py
index ef535ee3..ed498847 100644
--- a/src/replit_river/client_session.py
+++ b/src/replit_river/client_session.py
@@ -252,7 +252,11 @@ async def send_rpc(
                 except Exception as e:
                     raise RiverException("error_deserializer", str(e)) from e
                 raise exception_from_message(error.code)(
-                    error.code, error.message, service_name, procedure_name
+                    error.code,
+                    error.message,
+                    service_name,
+                    procedure_name,
+                    underlying_error=error,
                 )
             return response_deserializer(response["payload"])
         except RiverException as e:
@@ -338,7 +342,11 @@ async def send_upload(
                 except Exception as e:
                     raise RiverException("error_deserializer", str(e)) from e
                 raise exception_from_message(error.code)(
-                    error.code, error.message, service_name, procedure_name
+                    error.code,
+                    error.message,
+                    service_name,
+                    procedure_name,
+                    underlying_error=error,
                 )
 
             return response_deserializer(response["payload"])
diff --git a/src/replit_river/error_schema.py b/src/replit_river/error_schema.py
index 94a6789a..d6a316c1 100644
--- a/src/replit_river/error_schema.py
+++ b/src/replit_river/error_schema.py
@@ -51,12 +51,18 @@ class RiverServiceException(RiverException):
     """Exception raised by river as a result of a fault in the service running river."""
 
     def __init__(
-        self, code: str, message: str, service: str | None, procedure: str | None
+        self,
+        code: str,
+        message: str,
+        service: str | None,
+        procedure: str | None,
+        underlying_error: RiverError | None = None,
     ) -> None:
         self.code = code
         self.message = message
         self.service = service
         self.procedure = procedure
+        self.underlying_error = underlying_error
         service = service or "N/A"
         procedure = procedure or "N/A"
         msg = (
diff --git a/src/replit_river/v2/session.py b/src/replit_river/v2/session.py
index 9d8ce129..f7bfe4ed 100644
--- a/src/replit_river/v2/session.py
+++ b/src/replit_river/v2/session.py
@@ -790,7 +790,11 @@ async def send_rpc[R, A](
                 except Exception as e:
                     raise RiverException("error_deserializer", str(e)) from e
                 raise exception_from_message(error.code)(
-                    error.code, error.message, service_name, procedure_name
+                    error.code,
+                    error.message,
+                    service_name,
+                    procedure_name,
+                    underlying_error=error,
                 )
 
             return response_deserializer(result["payload"])
@@ -899,7 +903,11 @@ async def send_upload[I, R, A](
                 except Exception as e:
                     raise RiverException("error_deserializer", str(e)) from e
                 raise exception_from_message(error.code)(
-                    error.code, error.message, service_name, procedure_name
+                    error.code,
+                    error.message,
+                    service_name,
+                    procedure_name,
+                    underlying_error=error,
                 )
 
             return response_deserializer(result["payload"])