diff --git a/CHANGES.md b/CHANGES.md
index 426768a1..b838437b 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -43,6 +43,7 @@
 
 - add `write_connection_pool` option in `stac_fastapi.pgstac.db.connect_to_db` function
 - add `write_postgres_settings` option in `stac_fastapi.pgstac.db.connect_to_db` function to set specific settings for the `writer` DB connection pool
+- add specific error message when trying to create `Item` with null geometry (not supported by PgSTAC)
 
 ### removed
 
diff --git a/stac_fastapi/pgstac/transactions.py b/stac_fastapi/pgstac/transactions.py
index 27d3ae03..f4ed11c9 100644
--- a/stac_fastapi/pgstac/transactions.py
+++ b/stac_fastapi/pgstac/transactions.py
@@ -57,6 +57,12 @@ def _validate_item(
 
         self._validate_id(body_item_id, request.app.state.settings)
 
+        if item.get("geometry", None) is None:
+            raise HTTPException(
+                status_code=400,
+                detail=f"Missing or null `geometry` for Item ({body_item_id}). Geometry is required in pgstac.",
+            )
+
         if body_collection_id is not None and collection_id != body_collection_id:
             raise HTTPException(
                 status_code=400,
diff --git a/tests/clients/test_postgres.py b/tests/clients/test_postgres.py
index 4e066945..cf1bf141 100644
--- a/tests/clients/test_postgres.py
+++ b/tests/clients/test_postgres.py
@@ -152,6 +152,20 @@ async def test_create_item_bad_body(
     assert resp.status_code == 400
 
 
+async def test_create_item_no_geometry(
+    app_client, load_test_data: Callable, load_test_collection
+):
+    """Items with missing or null Geometry should return an error"""
+    coll = load_test_collection
+
+    item = load_test_data("test_item.json")
+    _ = item.pop("bbox")
+    item["geometry"] = None
+    resp = await app_client.post(f"/collections/{coll['id']}/items", json=item)
+    assert resp.status_code == 400
+    assert "Geometry is required in pgstac." in resp.json()["detail"]
+
+
 async def test_update_item(app_client, load_test_collection, load_test_item):
     coll = load_test_collection
     item = load_test_item