diff --git a/pelican/generators.py b/pelican/generators.py
index 099a2a8d..a7fef150 100644
--- a/pelican/generators.py
+++ b/pelican/generators.py
@@ -213,11 +213,11 @@ class ArticlesGenerator(Generator):
             arts.sort(key=attrgetter('date'), reverse=True)
             if self.settings.get('CATEGORY_FEED_ATOM'):
                 writer.write_feed(arts, self.context,
-                                  self.settings['CATEGORY_FEED_ATOM'] % cat)
+                                  self.settings['CATEGORY_FEED_ATOM'] % cat.slug)
 
             if self.settings.get('CATEGORY_FEED_RSS'):
                 writer.write_feed(arts, self.context,
-                                  self.settings['CATEGORY_FEED_RSS'] % cat,
+                                  self.settings['CATEGORY_FEED_RSS'] % cat.slug,
                                   feed_type='rss')
 
         if (self.settings.get('TAG_FEED_ATOM')
@@ -226,11 +226,11 @@ class ArticlesGenerator(Generator):
                 arts.sort(key=attrgetter('date'), reverse=True)
                 if self.settings.get('TAG_FEED_ATOM'):
                     writer.write_feed(arts, self.context,
-                                      self.settings['TAG_FEED_ATOM'] % tag)
+                                      self.settings['TAG_FEED_ATOM'] % tag.slug)
 
                 if self.settings.get('TAG_FEED_RSS'):
                     writer.write_feed(arts, self.context,
-                                      self.settings['TAG_FEED_RSS'] % tag,
+                                      self.settings['TAG_FEED_RSS'] % tag.slug,
                                       feed_type='rss')
 
         if (self.settings.get('TRANSLATION_FEED_ATOM')
diff --git a/pelican/themes/simple/templates/base.html b/pelican/themes/simple/templates/base.html
index 3ea2e8b9..212aef5e 100644
--- a/pelican/themes/simple/templates/base.html
+++ b/pelican/themes/simple/templates/base.html
@@ -16,17 +16,17 @@
         {% if FEED_RSS %}
         <link href="{{ FEED_DOMAIN }}/{{ FEED_RSS }}" type="application/rss+xml" rel="alternate" title="{{ SITENAME }} RSS Feed" />
         {% endif %}
-        {% if CATEGORY_FEED_ATOM %}
-        <link href="{{ FEED_DOMAIN }}/{{ CATEGORY_FEED_ATOM|format(category) }}" type="application/atom+xml" rel="alternate" title="{{ SITENAME }} Categories Atom Feed" />
+        {% if CATEGORY_FEED_ATOM and category %}
+        <link href="{{ FEED_DOMAIN }}/{{ CATEGORY_FEED_ATOM|format(category.slug) }}" type="application/atom+xml" rel="alternate" title="{{ SITENAME }} Categories Atom Feed" />
         {% endif %}
-        {% if CATEGORY_FEED_RSS %}
-        <link href="{{ FEED_DOMAIN }}/{{ CATEGORY_FEED_RSS|format(category) }}" type="application/rss+xml" rel="alternate" title="{{ SITENAME }} Categories RSS Feed" />
+        {% if CATEGORY_FEED_RSS and category %}
+        <link href="{{ FEED_DOMAIN }}/{{ CATEGORY_FEED_RSS|format(category.slug) }}" type="application/rss+xml" rel="alternate" title="{{ SITENAME }} Categories RSS Feed" />
         {% endif %}
-        {% if TAG_FEED_ATOM %}
-        <link href="{{ FEED_DOMAIN }}/{{ TAG_FEED_ATOM|format(tag) }}" type="application/atom+xml" rel="alternate" title="{{ SITENAME }} Tags Atom Feed" />
+        {% if TAG_FEED_ATOM and tag %}
+        <link href="{{ FEED_DOMAIN }}/{{ TAG_FEED_ATOM|format(tag.slug) }}" type="application/atom+xml" rel="alternate" title="{{ SITENAME }} Tags Atom Feed" />
         {% endif %}
-        {% if TAG_FEED_RSS %}
-        <link href="{{ FEED_DOMAIN }}/{{ TAG_FEED_RSS|format(tag) }}" type="application/rss+xml" rel="alternate" title="{{ SITENAME }} Tags RSS Feed" />
+        {% if TAG_FEED_RSS and tag %}
+        <link href="{{ FEED_DOMAIN }}/{{ TAG_FEED_RSS|format(tag.slug) }}" type="application/rss+xml" rel="alternate" title="{{ SITENAME }} Tags RSS Feed" />
         {% endif %}
         {% endblock head %}
 </head>