diff --git a/oml/item/handlers.py b/oml/item/handlers.py
index 19d6460..b20001a 100644
--- a/oml/item/handlers.py
+++ b/oml/item/handlers.py
@@ -17,7 +17,8 @@ import db
 import settings
 import tornado.web
 import tornado.gen
-import tornado.concurrent
+from concurrent.futures import ThreadPoolExecutor
+from tornado.concurrent import run_on_executor
 
 from oxtornado import json_dumps, json_response
 
@@ -27,6 +28,8 @@ import state
 import logging
 logger = logging.getLogger(__name__)
 
+MAX_WORKERS = 4
+
 
 class OptionalBasicAuthMixin(object):
     class SendChallenge(Exception):
@@ -177,6 +180,7 @@ class ReaderHandler(OMLHandler):
         return serve_static(self, path, 'text/html')
 
 class UploadHandler(OMLHandler):
+    executor = ThreadPoolExecutor(max_workers=MAX_WORKERS)
 
     def initialize(self, context=None):
         self._context = context
@@ -184,7 +188,60 @@ class UploadHandler(OMLHandler):
     def get(self):
         self.write('use POST')
 
-    @tornado.web.asynchronous
+    @run_on_executor
+    def save_files(self, request):
+        listname = request.arguments.get('list', None)
+        if listname:
+            listname = listname[0]
+            if isinstance(listname, bytes):
+                listname = listname.decode('utf-8')
+        with self._context():
+            prefs = settings.preferences
+            ids = []
+            for upload in request.files.get('files', []):
+                filename = upload.filename
+                id = get_id(data=upload.body)
+                ids.append(id)
+                file = File.get(id)
+                if not file or not os.path.exists(file.fullpath()):
+                    logger.debug('add %s to library', id)
+                    prefix_books = os.path.join(os.path.expanduser(prefs['libraryPath']), 'Books' + os.sep)
+                    prefix_imported = os.path.join(prefix_books, '.import' + os.sep)
+                    ox.makedirs(prefix_imported)
+                    import_name = os.path.join(prefix_imported, filename)
+                    n = 1
+                    while os.path.exists(import_name):
+                        n += 1
+                        name, extension = filename.rsplit('.', 1)
+                        if extension == 'kepub':
+                            extension = 'epub'
+                        import_name = os.path.join(prefix_imported, '%s [%d].%s' % (name, n, extension))
+                    with open(import_name, 'wb') as fd:
+                        fd.write(upload.body)
+                    file = add_file(id, import_name, prefix_books)
+                    file.move()
+                else:
+                    user = state.user()
+                    if not file.item:
+                        item = Item.get_or_create(id=file.sha1, info=file.info)
+                        file.item_id = item.id
+                        state.db.session.add(file)
+                        state.db.session.commit()
+                    else:
+                        item = file.item
+                    if user not in item.users:
+                        logger.debug('add %s to local user', id)
+                        item.add_user(user)
+                        add_record('additem', item.id, file.info)
+                        add_record('edititem', item.id, item.meta)
+                        item.update()
+        if listname and ids:
+            list_ = List.get(settings.USER_ID, listname)
+            if list_:
+                list_.add_items(ids)
+        response = json_response({'ids': ids})
+        return response
+
     @tornado.gen.coroutine
     def post(self):
         if 'origin' in self.request.headers and self.request.host not in self.request.headers['origin']:
@@ -193,60 +250,7 @@ class UploadHandler(OMLHandler):
             self.write('')
             return
 
-        def save_files(context, request, callback):
-            listname = request.arguments.get('list', None)
-            if listname:
-                listname = listname[0]
-                if isinstance(listname, bytes):
-                    listname = listname.decode('utf-8')
-            with context():
-                prefs = settings.preferences
-                ids = []
-                for upload in request.files.get('files', []):
-                    filename = upload.filename
-                    id = get_id(data=upload.body)
-                    ids.append(id)
-                    file = File.get(id)
-                    if not file or not os.path.exists(file.fullpath()):
-                        logger.debug('add %s to library', id)
-                        prefix_books = os.path.join(os.path.expanduser(prefs['libraryPath']), 'Books' + os.sep)
-                        prefix_imported = os.path.join(prefix_books, '.import' + os.sep)
-                        ox.makedirs(prefix_imported)
-                        import_name = os.path.join(prefix_imported, filename)
-                        n = 1
-                        while os.path.exists(import_name):
-                            n += 1
-                            name, extension = filename.rsplit('.', 1)
-                            if extension == 'kepub':
-                                extension = 'epub'
-                            import_name = os.path.join(prefix_imported, '%s [%d].%s' % (name, n, extension))
-                        with open(import_name, 'wb') as fd:
-                            fd.write(upload.body)
-                        file = add_file(id, import_name, prefix_books)
-                        file.move()
-                    else:
-                        user = state.user()
-                        if not file.item:
-                            item = Item.get_or_create(id=file.sha1, info=file.info)
-                            file.item_id = item.id
-                            state.db.session.add(file)
-                            state.db.session.commit()
-                        else:
-                            item = file.item
-                        if user not in item.users:
-                            logger.debug('add %s to local user', id)
-                            item.add_user(user)
-                            add_record('additem', item.id, file.info)
-                            add_record('edititem', item.id, item.meta)
-                            item.update()
-            if listname and ids:
-                l = List.get(settings.USER_ID, listname)
-                if l:
-                    l.add_items(ids)
-            response = json_response({'ids': ids})
-            callback(response)
-
-        response = yield tornado.gen.Task(save_files, self._context, self.request)
+        response = yield self.save_files(self.request)
         if 'status' not in response:
             response = json_response(response)
         response = json_dumps(response)