diff --git a/apps/documents/__init__.py b/apps/documents/__init__.py
index 9326037834..2fd33a65a0 100644
--- a/apps/documents/__init__.py
+++ b/apps/documents/__init__.py
@@ -43,7 +43,7 @@ from .links import (document_page_transformation_list, document_page_transformat
     document_page_navigation_last, document_page_zoom_in, document_page_zoom_out,
     document_page_rotate_right, document_page_rotate_left, document_page_view_reset,
     document_multiple_clear_transformations, document_multiple_delete,
-    document_multiple_download)
+    document_multiple_download, document_version_text_compare)
 from .links import document_clear_image_cache
 from .statistics import get_statistics
 
@@ -59,6 +59,7 @@ bind_links([Document], [document_view_simple, document_edit, document_print, doc
 
 # Document Version links
 bind_links([DocumentVersion], [document_version_revert, document_version_download])
+bind_links(['document_version_list', 'upload_version', 'document_version_revert', 'document_version_text_compare', 'document_version_show_diff_text'], [document_version_text_compare], menu_name='sidebar')
 
 secondary_menu_links = [document_list_recent, document_list]
 
diff --git a/apps/documents/forms.py b/apps/documents/forms.py
index 111ab80484..e39d45b29c 100644
--- a/apps/documents/forms.py
+++ b/apps/documents/forms.py
@@ -321,3 +321,33 @@ class DocumentDownloadForm(forms.Form):
         if len(self.document_versions) > 1:
             self.fields['compressed'].initial = True
             self.fields['compressed'].widget.attrs.update({'disabled': True})
+
+
+class DocumentVersionCompareForm(forms.Form):
+    left_version = forms.ChoiceField(label=_(u'Source version'), required=True)
+    right_version = forms.ChoiceField(label=_(u'Destination version'), required=True)
+    
+    def make_choices(self):
+        return [(version.pk, unicode(version)) for version in self.document.versions.all()]
+    
+    def __init__(self, *args, **kwargs):
+        self.document = kwargs.pop('document')
+        super(DocumentVersionCompareForm, self).__init__(*args, **kwargs)
+        choices = self.make_choices()
+        self.fields['left_version'].choices = choices
+        self.fields['left_version'].initial = choices[-2][0] if len(choices) > 1 else choices[-1][0]
+        
+        self.fields['right_version'].choices = choices
+        self.fields['right_version'].initial = choices[-1][0]
+
+
+class DocumentVersionDiffForm(forms.Form):
+    def __init__(self, *args, **kwargs):
+        contents = kwargs.pop('contents', None)
+        super(DocumentVersionDiffForm, self).__init__(*args, **kwargs)
+        self.fields['contents'].initial = contents
+
+    contents = forms.CharField(
+        label=_(u'Contents'),
+        widget=TextAreaDiv()
+    )
diff --git a/apps/documents/links.py b/apps/documents/links.py
index 62fe8a33f6..7330bbd92c 100644
--- a/apps/documents/links.py
+++ b/apps/documents/links.py
@@ -11,7 +11,8 @@ from .permissions import (PERMISSION_DOCUMENT_CREATE,
     PERMISSION_DOCUMENT_TRANSFORM, PERMISSION_DOCUMENT_TOOLS,
     PERMISSION_DOCUMENT_EDIT, PERMISSION_DOCUMENT_VERSION_REVERT,
     PERMISSION_DOCUMENT_TYPE_EDIT, PERMISSION_DOCUMENT_TYPE_DELETE,
-    PERMISSION_DOCUMENT_TYPE_CREATE, PERMISSION_DOCUMENT_TYPE_VIEW)
+    PERMISSION_DOCUMENT_TYPE_CREATE, PERMISSION_DOCUMENT_TYPE_VIEW,
+    PERMISSION_DOCUMENT_VERSIONS_TEXT_COMPARE)
 
 from .conf.settings import ZOOM_MAX_LEVEL, ZOOM_MIN_LEVEL
 
@@ -83,6 +84,7 @@ document_page_view_reset = Link(text=_(u'reset view'), klass='no-parent-history'
 # Document versions
 document_version_list = Link(text=_(u'versions'), view='document_version_list', args='object.pk', sprite='page_world', permissions=[PERMISSION_DOCUMENT_VIEW])
 document_version_revert = Link(text=_(u'revert'), view='document_version_revert', args='object.pk', sprite='page_refresh', permissions=[PERMISSION_DOCUMENT_VERSION_REVERT], conditional_disable=is_current_version)
+document_version_text_compare = Link(text=_(u'compare (text)'), view='document_version_text_compare', args='object.pk', sprite='table_relationship', permissions=[PERMISSION_DOCUMENT_VERSIONS_TEXT_COMPARE])
 
 # Document type related links
 document_type_list = Link(text=_(u'document type list'), view='document_type_list', sprite='layout', permissions=[PERMISSION_DOCUMENT_TYPE_VIEW])
diff --git a/apps/documents/permissions.py b/apps/documents/permissions.py
index 93d6bda51a..576a3a37c9 100644
--- a/apps/documents/permissions.py
+++ b/apps/documents/permissions.py
@@ -23,3 +23,5 @@ PERMISSION_DOCUMENT_TYPE_VIEW = Permission.objects.register(documents_setup_name
 PERMISSION_DOCUMENT_TYPE_EDIT = Permission.objects.register(documents_setup_namespace, 'document_type_edit', _(u'Edit document types'))
 PERMISSION_DOCUMENT_TYPE_DELETE = Permission.objects.register(documents_setup_namespace, 'document_type_delete', _(u'Delete document types'))
 PERMISSION_DOCUMENT_TYPE_CREATE = Permission.objects.register(documents_setup_namespace, 'document_type_create', _(u'Create document types'))
+
+PERMISSION_DOCUMENT_VERSIONS_TEXT_COMPARE = Permission.objects.register(documents_setup_namespace, 'document_versions_text_compare', _(u'Compare document version textually'))
diff --git a/apps/documents/urls.py b/apps/documents/urls.py
index 2a2cfcb7db..67708c097c 100644
--- a/apps/documents/urls.py
+++ b/apps/documents/urls.py
@@ -36,6 +36,8 @@ urlpatterns = patterns('documents.views',
     url(r'^(?P<document_pk>\d+)/version/all/$', 'document_version_list', (), 'document_version_list'),
     url(r'^document/version/(?P<document_version_pk>\d+)/download/$', 'document_download', (), 'document_version_download'),
     url(r'^document/version/(?P<document_version_pk>\d+)/revert/$', 'document_version_revert', (), 'document_version_revert'),
+    url(r'^document/(?P<document_pk>\d+)/version_compare/text/$', 'document_version_text_compare', (), 'document_version_text_compare'),
+    url(r'^document/version/show/text/diff/(?P<left_document_version_pk>\d+)/vs/(?P<right_document_version_pk>\d+)/$', 'document_version_show_diff_text', (), 'document_version_show_diff_text'),
 
     url(r'^multiple/clear_transformations/$', 'document_multiple_clear_transformations', (), 'document_multiple_clear_transformations'),
     url(r'^duplicates/list/$', 'document_find_all_duplicates', (), 'document_find_all_duplicates'),
diff --git a/apps/documents/views.py b/apps/documents/views.py
index 839bbb36f0..9744c4bb5d 100644
--- a/apps/documents/views.py
+++ b/apps/documents/views.py
@@ -40,17 +40,20 @@ from .permissions import (PERMISSION_DOCUMENT_CREATE,
     PERMISSION_DOCUMENT_TRANSFORM, PERMISSION_DOCUMENT_TOOLS,
     PERMISSION_DOCUMENT_EDIT, PERMISSION_DOCUMENT_VERSION_REVERT,
     PERMISSION_DOCUMENT_TYPE_EDIT, PERMISSION_DOCUMENT_TYPE_DELETE,
-    PERMISSION_DOCUMENT_TYPE_CREATE, PERMISSION_DOCUMENT_TYPE_VIEW)
+    PERMISSION_DOCUMENT_TYPE_CREATE, PERMISSION_DOCUMENT_TYPE_VIEW,
+    PERMISSION_DOCUMENT_VERSIONS_TEXT_COMPARE)
 from .events import history_document_edited
 from .forms import (DocumentForm_edit, DocumentPropertiesForm,
         DocumentPreviewForm, DocumentPageForm,
         DocumentPageTransformationForm, DocumentContentForm,
         DocumentPageForm_edit, DocumentPageForm_text, PrintForm,
         DocumentTypeForm, DocumentTypeFilenameForm,
-        DocumentTypeFilenameForm_create, DocumentDownloadForm)
+        DocumentTypeFilenameForm_create, DocumentDownloadForm,
+        DocumentVersionCompareForm, DocumentVersionDiffForm)
 from .models import (Document, DocumentType, DocumentPage,
     DocumentPageTransformation, RecentDocument, DocumentTypeFilename,
     DocumentVersion)
+from .widgets import diff_widget
 
 logger = logging.getLogger(__name__)
 
@@ -1364,3 +1367,60 @@ def document_version_revert(request, document_version_pk):
         'message': _(u'All later version after this one will be deleted too.'),
         'form_icon': u'page_refresh.png',
     }, context_instance=RequestContext(request))
+
+
+def document_version_text_compare(request, document_pk):
+    document = get_object_or_404(Document, pk=document_pk)
+
+    try:
+        Permission.objects.check_permissions(request.user, [PERMISSION_DOCUMENT_VERSIONS_TEXT_COMPARE])
+    except PermissionDenied:
+        AccessEntry.objects.check_access(PERMISSION_DOCUMENT_VERSIONS_TEXT_COMPARE, request.user, document)
+
+    RecentDocument.objects.add_document_for_user(request.user, document)
+
+    if request.method == 'POST':
+        form = DocumentVersionCompareForm(document=document, data=request.POST)
+        if form.is_valid():
+            return HttpResponseRedirect(reverse('document_version_show_diff_text', args=[form.cleaned_data['left_version'], form.cleaned_data['right_version']]))
+    else:
+        form = DocumentVersionCompareForm(document=document)
+
+    return render_to_response('generic_form.html', {
+        'object': document,
+        'title': _(u'Textually compare versions of document: %s') % document,
+        'form': form,
+        'submit_label': _(u'Compare'),
+        'submit_icon_famfam': 'table_relationship',
+    },
+    context_instance=RequestContext(request))
+
+
+def document_version_show_diff_text(request, left_document_version_pk, right_document_version_pk):
+    left_document_version = get_object_or_404(DocumentVersion, pk=left_document_version_pk)
+    right_document_version = get_object_or_404(DocumentVersion, pk=right_document_version_pk)
+
+    try:
+        Permission.objects.check_permissions(request.user, [PERMISSION_DOCUMENT_VERSIONS_TEXT_COMPARE])
+    except PermissionDenied:
+        # Make sure user has the compare permission for both document
+        # versions' root documents
+        AccessEntry.objects.check_access(PERMISSION_DOCUMENT_VERSIONS_TEXT_COMPARE, request.user, left_document_version.document)
+        AccessEntry.objects.check_access(PERMISSION_DOCUMENT_VERSIONS_TEXT_COMPARE, request.user, right_document_version.document)
+
+    context = {
+        'form': DocumentVersionDiffForm(contents=diff_widget(left_document_version.content, right_document_version.content)),
+        'read_only': True
+    }
+
+    if left_document_version.document == right_document_version.document:
+        context['object'] = left_document_version.document
+        context['title'] = _(u'Textual difference between version %(version1)s and %(version2)s of document: %(document)s') % {
+            'version1': left_document_version, 'version2': right_document_version,
+            'document': left_document_version.document}
+    else:
+        context['title'] = _(u'Textual difference between document: %(document1)s and %(document2)s.') % {
+            'document1': left_document_version.document, 'document2': right_document_version.document}
+
+    return render_to_response('generic_form.html', context,
+        context_instance=RequestContext(request))
diff --git a/apps/documents/widgets.py b/apps/documents/widgets.py
index 705c28cd82..a7b46294d3 100644
--- a/apps/documents/widgets.py
+++ b/apps/documents/widgets.py
@@ -1,5 +1,7 @@
 from __future__ import absolute_import
 
+import diff_match_patch
+
 from django.utils.safestring import mark_safe
 from django.conf import settings
 from django.utils.translation import ugettext_lazy as _
@@ -85,3 +87,18 @@ def document_html_widget(document, view='document_thumbnail', click_view=None, p
     )
 
     return mark_safe(u''.join(result))
+
+
+def diff_widget(version1, version2):
+    
+    dmp = diff_match_patch.diff_match_patch()
+    dmp.Diff_Timeout = 1  # Don't spend more than 1 seconds on a diff.
+
+    differences = dmp.diff_main(version1, version2)
+    dmp.diff_cleanupSemantic(differences)
+    pretty = dmp.diff_prettyHtml(differences)
+    #patch=dmp.patch_make(differences)
+    #text = dmp.patch_toText(patch)
+    return mark_safe(dmp.diff_prettyHtml(differences))
+    
+    
diff --git a/apps/sources/__init__.py b/apps/sources/__init__.py
index 6ed77c392b..64db8aeaab 100644
--- a/apps/sources/__init__.py
+++ b/apps/sources/__init__.py
@@ -48,7 +48,7 @@ bind_links([WatchFolder], [setup_web_form_list, setup_staging_folder_list, setup
 bind_links([WatchFolder], [setup_source_transformation_list, setup_source_edit, setup_source_delete])
 
 # Document version
-bind_links(['document_version_list', 'upload_version', 'document_version_revert'], [upload_version], menu_name='sidebar')
+bind_links(['document_version_list', 'upload_version', 'document_version_revert', 'document_version_text_compare', 'document_version_show_diff_text'], [upload_version], menu_name='sidebar')
 
 bind_links(['setup_source_transformation_create', 'setup_source_transformation_edit', 'setup_source_transformation_delete', 'setup_source_transformation_list'], [setup_source_transformation_create], menu_name='sidebar')
 
diff --git a/requirements/production.txt b/requirements/production.txt
index 883346078d..9055a27f2f 100644
--- a/requirements/production.txt
+++ b/requirements/production.txt
@@ -72,3 +72,4 @@ GitPython==0.3.2.RC1
 
 elementtree==1.2.7-20070827-preview
 Pygments==1.5
+diff-match-patch==20120106