diff --git a/atlas/views.py b/atlas/views.py
index 48e7926c..740fd600 100755
--- a/atlas/views.py
+++ b/atlas/views.py
@@ -1229,7 +1229,17 @@ def case_search(request):
 
     # Exclude recent cases from the main search results to avoid duplication
     recent_pks = [c.pk for c in recent_cases]
-    cases = qs.exclude(pk__in=recent_pks).order_by("title")[:30]
+
+    # Build the base queryset for results, apply excludes first (before slicing)
+    cases_qs = qs.exclude(pk__in=recent_pks)
+
+    # Also exclude any cases that are already present in the collection
+    if collection is not None:
+        existing_pks = list(collection.cases.values_list("pk", flat=True))
+        if existing_pks:
+            cases_qs = cases_qs.exclude(pk__in=existing_pks)
+
+    cases = cases_qs.order_by("title")[:30]
 
     return render(
         request,