diff --git a/taskiq/brokers/inmemory_broker.py b/taskiq/brokers/inmemory_broker.py
index 807f1e75..3e8c790a 100644
--- a/taskiq/brokers/inmemory_broker.py
+++ b/taskiq/brokers/inmemory_broker.py
@@ -44,7 +44,8 @@ async def set_result(self, task_id: str, result: TaskiqResult[_ReturnType]) -> N
         :param result: result of an execution.
         """
         if (
-            self.max_stored_results != -1
+            task_id not in self.results
+            and self.max_stored_results != -1
             and len(self.results) >= self.max_stored_results
         ):
             self.results.popitem(last=False)
@@ -95,7 +96,8 @@ async def set_progress(
         :param progress: task execution progress
         """
         if (
-            self.max_stored_results != -1
+            task_id not in self.progress
+            and self.max_stored_results != -1
             and len(self.progress) >= self.max_stored_results
         ):
             self.progress.popitem(last=False)
diff --git a/tests/brokers/test_inmemory_result_backend.py b/tests/brokers/test_inmemory_result_backend.py
new file mode 100644
index 00000000..c2a4641e
--- /dev/null
+++ b/tests/brokers/test_inmemory_result_backend.py
@@ -0,0 +1,74 @@
+import pytest
+
+from taskiq.brokers.inmemory_broker import InmemoryResultBackend
+from taskiq.depends.progress_tracker import TaskProgress
+from taskiq.result import TaskiqResult
+
+
+@pytest.mark.parametrize("capacity", [1, 2, -1])
+@pytest.mark.parametrize("update_first", [True, False])
+async def test_result_updates_preserve_cached_tasks(
+    capacity: int,
+    *,
+    update_first: bool,
+) -> None:
+    backend = InmemoryResultBackend[int](max_stored_results=capacity)
+    task_ids = ["first"] if capacity == 1 else ["first", "second"]
+    for task_id in task_ids:
+        await backend.set_result(
+            task_id,
+            TaskiqResult(is_err=False, return_value=0, execution_time=0),
+        )
+
+    updated_id = task_ids[0] if update_first else task_ids[-1]
+    for value in (1, 2):
+        await backend.set_result(
+            updated_id,
+            TaskiqResult(is_err=False, return_value=value, execution_time=0),
+        )
+        for task_id in task_ids:
+            assert await backend.is_result_ready(task_id)
+        assert (await backend.get_result(updated_id)).return_value == value
+
+    await backend.set_result(
+        "new",
+        TaskiqResult(is_err=False, return_value=3, execution_time=0),
+    )
+    assert await backend.is_result_ready("new")
+    assert await backend.is_result_ready("first") is (capacity == -1)
+    if capacity != 1:
+        assert await backend.is_result_ready("second")
+
+
+@pytest.mark.parametrize("capacity", [1, 2, -1])
+@pytest.mark.parametrize("update_first", [True, False])
+async def test_progress_updates_preserve_cached_tasks(
+    capacity: int,
+    *,
+    update_first: bool,
+) -> None:
+    backend = InmemoryResultBackend[int](max_stored_results=capacity)
+    task_ids = ["first"] if capacity == 1 else ["first", "second"]
+    for task_id in task_ids:
+        await backend.set_progress(
+            task_id,
+            TaskProgress(state="STARTED", meta=0),
+        )
+
+    updated_id = task_ids[0] if update_first else task_ids[-1]
+    for value in (1, 2):
+        await backend.set_progress(
+            updated_id,
+            TaskProgress(state="STARTED", meta=value),
+        )
+        for task_id in task_ids:
+            assert await backend.get_progress(task_id) is not None
+        progress = await backend.get_progress(updated_id)
+        assert progress is not None
+        assert progress.meta == value
+
+    await backend.set_progress("new", TaskProgress(state="STARTED", meta=3))
+    assert await backend.get_progress("new") is not None
+    assert (await backend.get_progress("first") is not None) is (capacity == -1)
+    if capacity != 1:
+        assert await backend.get_progress("second") is not None