Are you trying to use the {{MEDIA_URL}} template tag and see it resolving as blank?
You have most likely omitted the third optional argument to your render_to_response call in your underlying view.
Your code is something like this:
from django.shortcuts import render_to_response def awesomeView(request): return render_to_response('template.html', {})
It should be something like this:
from django.template import RequestContext from django.shortcuts import render_to_response def awesomeView(request): return render_to_response('template.html', {}, context_instance = RequestContext(request))