diff --git a/judge/forms.py b/judge/forms.py
index f8511fbc4..0a0de4325 100755
--- a/judge/forms.py
+++ b/judge/forms.py
@@ -198,7 +198,7 @@ def clean_code(self):
         if self.org_pk is None:
             return code
         org = Organization.objects.get(pk=self.org_pk)
-        prefix = ''.join(x for x in org.slug.lower() if x.isalpha()) + '_'
+        prefix = ''.join(x for x in org.slug.lower() if x.isalnum()) + '_'
         if not code.startswith(prefix):
             raise forms.ValidationError(_('Problem id code must starts with `%s`') % (prefix, ),
                                         'problem_id_invalid_prefix')
@@ -692,7 +692,7 @@ def clean_key(self):
         if self.org_pk is None:
             return key
         org = Organization.objects.get(pk=self.org_pk)
-        prefix = ''.join(x for x in org.slug.lower() if x.isalpha()) + '_'
+        prefix = ''.join(x for x in org.slug.lower() if x.isalnum()) + '_'
         if not key.startswith(prefix):
             raise forms.ValidationError(_('Contest id must starts with `%s`') % (prefix, ),
                                         'contest_id_invalid_prefix')
diff --git a/judge/views/organization.py b/judge/views/organization.py
index ba26a83c2..54fb59390 100644
--- a/judge/views/organization.py
+++ b/judge/views/organization.py
@@ -604,7 +604,7 @@ class ProblemCreateOrganization(AdminOrganizationMixin, ProblemCreate):
     def get_initial(self):
         initial = super(ProblemCreateOrganization, self).get_initial()
         initial = initial.copy()
-        initial['code'] = ''.join(x for x in self.organization.slug.lower() if x.isalpha()) + '_'
+        initial['code'] = ''.join(x for x in self.organization.slug.lower() if x.isalnum()) + '_'
         return initial
 
     def get_form_kwargs(self):
@@ -644,7 +644,7 @@ def form_valid(self, form):
         with revisions.create_revision(atomic=True):
             post = form.save()
             post.authors.add(self.request.user.profile)
-            post.slug = ''.join(x for x in self.organization.slug.lower() if x.isalpha())  # Initial post slug
+            post.slug = ''.join(x for x in self.organization.slug.lower() if x.isalnum())  # Initial post slug
             post.organization = self.organization
             post.save()
 
@@ -660,7 +660,7 @@ class ContestCreateOrganization(AdminOrganizationMixin, CreateContest):
     def get_initial(self):
         initial = super(ContestCreateOrganization, self).get_initial()
         initial = initial.copy()
-        initial['key'] = ''.join(x for x in self.organization.slug.lower() if x.isalpha()) + '_'
+        initial['key'] = ''.join(x for x in self.organization.slug.lower() if x.isalnum()) + '_'
         return initial
 
     def get_form_kwargs(self):