diff --git a/rhodecode/apps/my_account/views/my_account.py b/rhodecode/apps/my_account/views/my_account.py
--- a/rhodecode/apps/my_account/views/my_account.py
+++ b/rhodecode/apps/my_account/views/my_account.py
@@ -400,14 +400,15 @@ class MyAccountView(BaseAppView, DataGri
         c.active = 'bookmarks'
         return self._get_template_context(c)
 
-    def _process_entry(self, entry, user_id):
+    def _process_bookmark_entry(self, entry, user_id):
         position = safe_int(entry.get('position'))
-        if position is None:
+        cur_position = safe_int(entry.get('cur_position'))
+        if position is None or cur_position is None:
             return
 
         # check if this is an existing entry
         is_new = False
-        db_entry = UserBookmark().get_by_position_for_user(position, user_id)
+        db_entry = UserBookmark().get_by_position_for_user(cur_position, user_id)
 
         if db_entry and str2bool(entry.get('remove')):
             log.debug('Marked bookmark %s for deletion', db_entry)
@@ -446,12 +447,12 @@ class MyAccountView(BaseAppView, DataGri
             should_save = True
 
         if should_save:
-            log.debug('Saving bookmark %s, new:%s', db_entry, is_new)
             # mark user and position
             db_entry.user_id = user_id
             db_entry.position = position
             db_entry.title = entry.get('title')
             db_entry.redirect_url = entry.get('redirect_url') or default_redirect_url
+            log.debug('Saving bookmark %s, new:%s', db_entry, is_new)
 
             Session().add(db_entry)
 
@@ -468,15 +469,31 @@ class MyAccountView(BaseAppView, DataGri
         controls = peppercorn.parse(self.request.POST.items())
         user_id = c.user.user_id
 
+        # validate positions
+        positions = {}
+        for entry in controls.get('bookmarks', []):
+            position = safe_int(entry['position'])
+            if position is None:
+                continue
+
+            if position in positions:
+                h.flash(_("Position {} is defined twice. "
+                          "Please correct this error.").format(position), category='error')
+                return HTTPFound(h.route_path('my_account_bookmarks'))
+
+            entry['position'] = position
+            entry['cur_position'] = safe_int(entry.get('cur_position'))
+            positions[position] = entry
+
         try:
-            for entry in controls.get('bookmarks', []):
-                self._process_entry(entry, user_id)
+            for entry in positions.values():
+                self._process_bookmark_entry(entry, user_id)
 
             Session().commit()
             h.flash(_("Update Bookmarks"), category='success')
         except IntegrityError:
             h.flash(_("Failed to update bookmarks. "
-                      "Make sure an unique position is used"), category='error')
+                      "Make sure an unique position is used."), category='error')
 
         return HTTPFound(h.route_path('my_account_bookmarks'))
 
diff --git a/rhodecode/model/db.py b/rhodecode/model/db.py
--- a/rhodecode/model/db.py
+++ b/rhodecode/model/db.py
@@ -5085,7 +5085,7 @@ class UserBookmark(Base, BaseModel):
             .all()
 
     def __unicode__(self):
-        return u'<UserBookmark(%d @ %r)>' % (self.position, self.redirect_url)
+        return u'<UserBookmark(%s @ %r)>' % (self.position, self.redirect_url)
 
 
 class FileStore(Base, BaseModel):
diff --git a/rhodecode/templates/admin/my_account/my_account_bookmarks.mako b/rhodecode/templates/admin/my_account/my_account_bookmarks.mako
--- a/rhodecode/templates/admin/my_account/my_account_bookmarks.mako
+++ b/rhodecode/templates/admin/my_account/my_account_bookmarks.mako
@@ -1,13 +1,14 @@
 <%namespace name="dt" file="/data_table/_dt_elements.mako"/>
 
-<%def name="form_item(count, position=None, title=None, redirect_url=None, repo=None, repo_group=None)">
+<%def name="form_item(position=None, title=None, redirect_url=None, repo=None, repo_group=None)">
     <tr>
         <td class="td-align-top" >
             <div class="label">
                 <label for="position">${_('Position')}:</label>
             </div>
             <div class="input">
-                <input type="text" name="position" value="${position or count}" style="width: 40px"/>
+                <input type="text" name="position" value="${position}" style="width: 40px"/>
+                ${h.hidden('cur_position', position)}
             </div>
         </td>
 
@@ -91,14 +92,14 @@
         <table class="rctable">
         ## generate always 10 entries
         <input type="hidden" name="__start__" value="bookmarks:sequence"/>
-        % for cnt, item in enumerate((c.bookmark_items + [None for i in range(10)])[:10]):
+        % for item in (c.bookmark_items + [None for i in range(10)])[:10]:
             <input type="hidden" name="__start__" value="bookmark:mapping"/>
             % if item is None:
                 ## empty placehodlder
-                ${form_item(cnt)}
+                ${form_item()}
             % else:
                 ## actual entry
-                ${form_item(cnt, position=item.position, title=item.title, redirect_url=item.redirect_url, repo=item.repository, repo_group=item.repository_group)}
+                ${form_item(position=item.position, title=item.title, redirect_url=item.redirect_url, repo=item.repository, repo_group=item.repository_group)}
             % endif
             <input type="hidden" name="__end__" value="bookmark:mapping"/>
         % endfor