diff --git a/django/templatetags/cache.py b/django/templatetags/cache.py
index 056eadc7de..e431f99d0d 100644
--- a/django/templatetags/cache.py
+++ b/django/templatetags/cache.py
@@ -4,6 +4,7 @@ import hashlib
 from django.template import Library, Node, TemplateSyntaxError, Variable, VariableDoesNotExist
 from django.template import resolve_variable
 from django.core.cache import cache
+from django.utils.encoding import smart_bytes
 from django.utils.http import urlquote
 
 register = Library()
@@ -24,8 +25,9 @@ class CacheNode(Node):
             expire_time = int(expire_time)
         except (ValueError, TypeError):
             raise TemplateSyntaxError('"cache" tag got a non-integer timeout value: %r' % expire_time)
-        # Build a unicode key for this fragment and all vary-on's.
-        args = hashlib.md5(':'.join([urlquote(resolve_variable(var, context)) for var in self.vary_on]))
+        # Build a key for this fragment and all vary-on's.
+        key = smart_bytes(':'.join([urlquote(resolve_variable(var, context)) for var in self.vary_on]))
+        args = hashlib.md5(key)
         cache_key = 'template.cache.%s.%s' % (self.fragment_name, args.hexdigest())
         value = cache.get(cache_key)
         if value is None: