diff --git a/cachetory/caches/sync.py b/cachetory/caches/sync.py
index 8674d81..0232976 100644
--- a/cachetory/caches/sync.py
+++ b/cachetory/caches/sync.py
@@ -138,12 +138,11 @@ def __delitem__(self, key: str) -> None:
         """
         Delete the cache item.
 
-        Warning:
-            This method **does not** currently adhere to the `object.__delitem__()` interface
-            in regard to the raised exceptions: `KeyError` **is not** raised when the key is missing.
-            See also [kpn/cachetory#67](https://github.com/kpn/cachetory/issues/67).
+        Raises:
+            KeyError: the key didn't exist
         """
-        self.delete(key)
+        if not self.delete(key):
+            raise KeyError(key)
 
     def __exit__(self, exc_type, exc_val, exc_tb) -> None:
         return self._backend.__exit__(exc_type, exc_val, exc_tb)
diff --git a/tests/caches/test_async.py b/tests/caches/test_async.py
index 01fd8e4..2a07947 100644
--- a/tests/caches/test_async.py
+++ b/tests/caches/test_async.py
@@ -15,31 +15,31 @@ async def memory_cache() -> Cache[int, bytes]:
 
 
 @mark.asyncio
-async def test_get_set_in_memory(memory_cache: Cache[int, bytes]):
+async def test_get_set_in_memory(memory_cache: Cache[int, bytes]) -> None:
     await memory_cache.set("foo", 42)
     assert await memory_cache.get("foo") == 42
 
 
 @mark.asyncio
-async def test_get_default(memory_cache: Cache[int, bytes]):
+async def test_get_default(memory_cache: Cache[int, bytes]) -> None:
     assert await memory_cache.get("missing", 100500) == 100500
 
 
 @mark.asyncio
-async def test_get_many(memory_cache: Cache[int, bytes]):
+async def test_get_many(memory_cache: Cache[int, bytes]) -> None:
     await memory_cache.set("foo", 42)
     assert await memory_cache.get_many("foo", "bar") == {"foo": 42}
 
 
 @mark.asyncio
-async def test_set_many(memory_cache: Cache[int, bytes]):
+async def test_set_many(memory_cache: Cache[int, bytes]) -> None:
     await memory_cache.set_many({"foo": 42, "bar": 100500})
     assert await memory_cache.get("foo") == 42
     assert await memory_cache.get("bar") == 100500
 
 
 @mark.asyncio
-async def test_delete(memory_cache: Cache[int, bytes]):
+async def test_delete(memory_cache: Cache[int, bytes]) -> None:
     await memory_cache.set("foo", 42)
     assert await memory_cache.delete("foo")
     assert not await memory_cache.delete("foo")
@@ -47,7 +47,7 @@ async def test_delete(memory_cache: Cache[int, bytes]):
 
 
 @mark.asyncio
-async def test_serialize_executor():
+async def test_serialize_executor() -> None:
     cache = Cache[int, bytes](
         serializer=serializers.from_url("pickle://"),
         backend=async_backends.from_url("memory://"),
@@ -59,7 +59,7 @@ async def test_serialize_executor():
 
 @if_redis_enabled
 @mark.asyncio
-async def test_get_set_in_redis():
+async def test_get_set_in_redis() -> None:
     cache = Cache[int, bytes](
         serializer=serializers.from_url("pickle+zlib://"),
         backend=async_backends.from_url("redis://localhost:6379"),
diff --git a/tests/caches/test_sync.py b/tests/caches/test_sync.py
index bf0428b..589db41 100644
--- a/tests/caches/test_sync.py
+++ b/tests/caches/test_sync.py
@@ -1,4 +1,4 @@
-from pytest import fixture
+from pytest import fixture, raises
 
 from cachetory import serializers
 from cachetory.backends import sync as sync_backends
@@ -14,46 +14,51 @@ def memory_cache() -> Cache[int, bytes]:
     )
 
 
-def test_get_set_in_memory(memory_cache: Cache[int, bytes]):
+def test_get_set_in_memory(memory_cache: Cache[int, bytes]) -> None:
     memory_cache.set("foo", 42)
     assert memory_cache.get("foo") == 42
 
 
-def test_set_item(memory_cache: Cache[int, bytes]):
+def test_set_item(memory_cache: Cache[int, bytes]) -> None:
     memory_cache["foo"] = 42
     assert memory_cache.get("foo") == 42
 
 
-def test_get_default(memory_cache: Cache[int, bytes]):
+def test_get_default(memory_cache: Cache[int, bytes]) -> None:
     assert memory_cache.get("missing", 100500) == 100500
 
 
-def test_get_many(memory_cache: Cache[int, bytes]):
+def test_get_many(memory_cache: Cache[int, bytes]) -> None:
     memory_cache.set("foo", 42)
     assert memory_cache.get_many("foo", "bar") == {"foo": 42}
 
 
-def test_set_many(memory_cache: Cache[int, bytes]):
+def test_set_many(memory_cache: Cache[int, bytes]) -> None:
     memory_cache.set_many({"foo": 42, "bar": 100500})
     assert memory_cache.get("foo") == 42
     assert memory_cache.get("bar") == 100500
 
 
-def test_delete(memory_cache: Cache[int, bytes]):
+def test_delete(memory_cache: Cache[int, bytes]) -> None:
     memory_cache.set("foo", 42)
     assert memory_cache.delete("foo")
     assert not memory_cache.delete("foo")
     assert memory_cache.get("foo") is None
 
 
-def test_del_item(memory_cache: Cache[int, bytes]):
+def test_del_item(memory_cache: Cache[int, bytes]) -> None:
     memory_cache.set("foo", 42)
     del memory_cache["foo"]
     assert memory_cache.get("foo") is None
 
 
+def test_del_missing_item(memory_cache: Cache[int, bytes]) -> None:
+    with raises(KeyError):
+        del memory_cache["missing"]
+
+
 @if_redis_enabled
-def test_get_set_in_redis():
+def test_get_set_in_redis() -> None:
     cache = Cache[int, bytes](
         serializer=serializers.from_url("pickle+zlib://"),
         backend=sync_backends.from_url("redis://localhost:6379"),