diff --git a/atlas/forms.py b/atlas/forms.py
index 027699f5..5aa955e3 100755
--- a/atlas/forms.py
+++ b/atlas/forms.py
@@ -464,10 +464,10 @@ class CaseSeriesForm(ModelForm):
 
 
 class CaseCollectionCaseForm(ModelForm):
-    def __init__(self, *args, user, **kwargs):
+    def __init__(self, *args, user, collection, **kwargs):
         super(CaseCollectionCaseForm, self).__init__(*args, **kwargs)
 
-        queryset = get_cases_available_to_user(user)
+        queryset = get_cases_available_to_user(user, collection=collection)
 
         self.fields["case"] = ModelChoiceField(
             required=False,
diff --git a/atlas/helpers.py b/atlas/helpers.py
index 06004996..24364b0c 100644
--- a/atlas/helpers.py
+++ b/atlas/helpers.py
@@ -1,8 +1,11 @@
 from atlas.models import Case
 
-def get_cases_available_to_user(user):
+def get_cases_available_to_user(user, collection=None):
     """Returns a queryset of cases available to the user"""
     queryset = Case.objects.filter(author=user) | Case.objects.filter(open_access=True)
+
+    if collection is not None:
+        queryset = queryset | collection.cases.all()
     return queryset.order_by("pk")
     if user.is_superuser:
         return Case.objects.all()
diff --git a/atlas/views.py b/atlas/views.py
index a9228ba4..131185e9 100755
--- a/atlas/views.py
+++ b/atlas/views.py
@@ -687,12 +687,12 @@ class CaseCollectionUpdate(RevisionMixin, AuthorOrCheckerRequiredMixin, UpdateVi
                 self.request.POST,
                 self.request.FILES,
                 instance=self.object,
-                form_kwargs={"user": self.request.user},
+                form_kwargs={"user": self.request.user, "collection": self.object},
             )
             context["case_formset"].full_clean()
         else:
             context["case_formset"] = CaseCollectionCaseFormSet(
-                instance=self.object, form_kwargs={"user": self.request.user}
+                instance=self.object, form_kwargs={"user": self.request.user, "collection": self.object}
             )
 
         context["collection"] = context["casecollection"]