diff --git a/stac_fastapi/api/stac_fastapi/api/errors.py b/stac_fastapi/api/stac_fastapi/api/errors.py
index dd1880fca..1575fad30 100644
--- a/stac_fastapi/api/stac_fastapi/api/errors.py
+++ b/stac_fastapi/api/stac_fastapi/api/errors.py
@@ -13,6 +13,7 @@
     ConflictError,
     DatabaseError,
     ForeignKeyError,
+    InvalidQueryParameter,
     NotFoundError,
 )
 
@@ -25,6 +26,7 @@
     ForeignKeyError: status.HTTP_422_UNPROCESSABLE_ENTITY,
     DatabaseError: status.HTTP_424_FAILED_DEPENDENCY,
     Exception: status.HTTP_500_INTERNAL_SERVER_ERROR,
+    InvalidQueryParameter: status.HTTP_400_BAD_REQUEST,
 }
 
 
diff --git a/stac_fastapi/pgstac/stac_fastapi/pgstac/core.py b/stac_fastapi/pgstac/stac_fastapi/pgstac/core.py
index f53850fed..b6aba0637 100644
--- a/stac_fastapi/pgstac/stac_fastapi/pgstac/core.py
+++ b/stac_fastapi/pgstac/stac_fastapi/pgstac/core.py
@@ -6,6 +6,7 @@
 
 import attr
 import orjson
+from asyncpg.exceptions import InvalidDatetimeFormatError
 from buildpg import render
 from fastapi import HTTPException
 from pydantic import ValidationError
@@ -16,7 +17,7 @@
 from stac_fastapi.pgstac.models.links import CollectionLinks, ItemLinks, PagingLinks
 from stac_fastapi.pgstac.types.search import PgstacSearch
 from stac_fastapi.types.core import AsyncBaseCoreClient
-from stac_fastapi.types.errors import NotFoundError
+from stac_fastapi.types.errors import InvalidQueryParameter, NotFoundError
 from stac_fastapi.types.stac import Collection, Collections, Item, ItemCollection
 
 NumType = Union[float, int]
@@ -116,14 +117,20 @@ async def _search_base(
         # pool = kwargs["request"].app.state.readpool
         req = search_request.json(exclude_none=True)
 
-        async with pool.acquire() as conn:
-            q, p = render(
-                """
-                SELECT * FROM search(:req::text::jsonb);
-                """,
-                req=req,
+        try:
+            async with pool.acquire() as conn:
+                q, p = render(
+                    """
+                    SELECT * FROM search(:req::text::jsonb);
+                    """,
+                    req=req,
+                )
+                items = await conn.fetchval(q, *p)
+        except InvalidDatetimeFormatError:
+            raise InvalidQueryParameter(
+                f"Datetime parameter {search_request.datetime} is invalid."
             )
-            items = await conn.fetchval(q, *p)
+
         next: Optional[str] = items.pop("next", None)
         prev: Optional[str] = items.pop("prev", None)
         collection = ItemCollection(**items)
diff --git a/stac_fastapi/pgstac/tests/api/test_api.py b/stac_fastapi/pgstac/tests/api/test_api.py
index 52c6ed5eb..71ee70e4b 100644
--- a/stac_fastapi/pgstac/tests/api/test_api.py
+++ b/stac_fastapi/pgstac/tests/api/test_api.py
@@ -104,3 +104,19 @@ async def test_app_sort_extension(load_test_data, app_client, load_test_collecti
     resp_json = resp.json()
     assert resp_json["features"][1]["id"] == first_item["id"]
     assert resp_json["features"][0]["id"] == second_item["id"]
+
+
+@pytest.mark.asyncio
+async def test_search_invalid_date(load_test_data, app_client, load_test_collection):
+    coll = load_test_collection
+    first_item = load_test_data("test_item.json")
+    resp = await app_client.post(f"/collections/{coll.id}/items", json=first_item)
+    assert resp.status_code == 200
+
+    params = {
+        "datetime": "2020-XX-01/2020-10-30",
+        "collections": [coll.id],
+    }
+
+    resp = await app_client.post("/search", json=params)
+    assert resp.status_code == 400
diff --git a/stac_fastapi/sqlalchemy/tests/api/test_api.py b/stac_fastapi/sqlalchemy/tests/api/test_api.py
index cd07f4500..cd860b642 100644
--- a/stac_fastapi/sqlalchemy/tests/api/test_api.py
+++ b/stac_fastapi/sqlalchemy/tests/api/test_api.py
@@ -101,3 +101,19 @@ def test_app_sort_extension(load_test_data, app_client, postgres_transactions):
     resp_json = resp.json()
     assert resp_json["features"][0]["id"] == first_item["id"]
     assert resp_json["features"][1]["id"] == second_item["id"]
+
+
+def test_search_invalid_date(load_test_data, app_client, postgres_transactions):
+    item = load_test_data("test_item.json")
+    postgres_transactions.create_item(item, request=MockStarletteRequest)
+
+    params = {
+        "datetime": "2020-XX-01/2020-10-30",
+        "collections": [item["collection"]],
+    }
+
+    resp = app_client.post("/search", json=params)
+    import json
+
+    print(json.dumps(resp.json(), indent=2))
+    assert resp.status_code == 400
diff --git a/stac_fastapi/types/stac_fastapi/types/errors.py b/stac_fastapi/types/stac_fastapi/types/errors.py
index 8796dc0a6..9bd51ed08 100644
--- a/stac_fastapi/types/stac_fastapi/types/errors.py
+++ b/stac_fastapi/types/stac_fastapi/types/errors.py
@@ -29,3 +29,13 @@ class DatabaseError(StacApiError):
     """Generic database errors."""
 
     pass
+
+
+class InvalidQueryParameter(StacApiError):
+    """Error for unknown or invalid query parameters.
+
+    Used to capture errors that should respond according to
+    http://docs.opengeospatial.org/is/17-069r3/17-069r3.html#query_parameters
+    """
+
+    pass