diff --git a/kbmanager/app_logic.py b/kbmanager/app_logic.py
index 6f30a1a..57cdc9c 100644
--- a/kbmanager/app_logic.py
+++ b/kbmanager/app_logic.py
@@ -99,7 +99,7 @@ async def upload_file_to_kb(self, file_path_str: str, kb_id: str):
             click.echo(f"Error: {e}", err=True)
             sys.exit(1)
 
-    async def upload_directory_to_kb(self, directory_path_str: str, kb_id: str, ignore_file_path: Optional[str] = None):
+    async def upload_directory_to_kb(self, directory_path_str: str, kb_id: str, ignore_file_path: Optional[str] = None, skip_existing: Optional[bool] = None):
         directory_path = Path(directory_path_str)
         if not directory_path.is_dir():
             raise FileOperationError(f"Directory not found: {directory_path_str}")
@@ -118,12 +118,29 @@ async def upload_directory_to_kb(self, directory_path_str: str, kb_id: str, igno
 
         files_to_upload: List[Tuple[Path, str]] = []
 
+        if skip_existing:
+            existing_files = [
+                f.meta.additional_properties["name"]
+                for f in await self._api.list_files_for_knowledge_base(kb_id)
+                if (
+                    hasattr(f, "meta")
+                    and isinstance(f.meta, self._api.FileMetadataResponseMeta)
+                    and "name" in f.meta.additional_properties
+                )
+            ]
+        else:
+            existing_files = []
+
         for root, _, files_in_dir in os.walk(directory_path):
             current_dir_path = Path(root)
             for file_name in files_in_dir:  # Renamed 'files' to 'files_in_dir' to avoid conflict with outer 'files_to_upload'
                 full_file_path = current_dir_path / file_name
                 relative_file_path = str(full_file_path.relative_to(directory_path))
 
+                if file_name in existing_files:
+                    logging.debug(f"Skipping existing file: {relative_file_path}")
+                    continue
+
                 if not kbignore_parser.is_ignored(str(relative_file_path)):
                     files_to_upload.append((full_file_path, relative_file_path))
                 else:
diff --git a/kbmanager/main.py b/kbmanager/main.py
index ab42754..9423202 100644
--- a/kbmanager/main.py
+++ b/kbmanager/main.py
@@ -184,16 +184,22 @@ async def upload_file(ctx: CLIContext, file_path, kb_id):
     type=click.Path(exists=True, dir_okay=False, resolve_path=True),
     help="Path to a .kbignore file. Defaults to .kbignore in the directory_path if not specified.",
 )
+@click.option(
+    "--skip-existing",
+    'skip_existing',
+    flag_value=True,
+    help="Skip existing files in knowledge base. Files are matched on file name.",
+)
 @click.pass_obj
 @coro
-async def upload_dir(ctx: CLIContext, directory_path, kb_id, ignore_file):
+async def upload_dir(ctx: CLIContext, directory_path, kb_id, ignore_file, skip_existing):
     """
     Uploads files from a directory to a specified knowledge base, respecting .kbignore.
     """
     ctx.init_api_client_and_app_logic()
     click.echo(f"Uploading directory: {directory_path}")
     try:
-        await ctx.app_logic.upload_directory_to_kb(directory_path, kb_id, ignore_file)
+        await ctx.app_logic.upload_directory_to_kb(directory_path, kb_id, ignore_file, skip_existing)
     except (APIError, FileOperationError) as e:
         logger.error(f"Could not complete directory upload: {e}")
         click.echo(f"Error: {e}", err=True)