diff --git a/src/spatialdata/testing.py b/src/spatialdata/testing.py
index 37ff1980d..1d1455479 100644
--- a/src/spatialdata/testing.py
+++ b/src/spatialdata/testing.py
@@ -183,3 +183,6 @@ def assert_spatial_data_objects_are_identical(
             check_transformations=check_transformations,
             check_metadata=check_metadata,
         )
+    # compare attrs
+    if check_metadata:
+        assert sdata0.attrs == sdata1.attrs
diff --git a/tests/io/test_attrs_io.py b/tests/io/test_attrs_io.py
new file mode 100644
index 000000000..4dda6f0d5
--- /dev/null
+++ b/tests/io/test_attrs_io.py
@@ -0,0 +1,120 @@
+"""Test attrs read/write for all SpatialData container formats."""
+
+import tempfile
+from pathlib import Path
+
+import pytest
+
+from spatialdata import SpatialData, read_zarr
+from spatialdata._io.format import (
+    SpatialDataContainerFormats,
+    SpatialDataContainerFormatType,
+)
+
+FORMAT_V01 = SpatialDataContainerFormats["0.1"]
+FORMAT_V02 = SpatialDataContainerFormats["0.2"]
+
+
+@pytest.mark.parametrize("sdata_container_format", [FORMAT_V01, FORMAT_V02])
+class TestAttrsIO:
+    """Test SpatialData.attrs read/write for all container formats."""
+
+    def test_attrs_write_and_read(
+        self,
+        sdata_container_format: SpatialDataContainerFormatType,
+    ) -> None:
+        """Test attrs with complex nested structures."""
+        with tempfile.TemporaryDirectory() as tmpdir:
+            f = Path(tmpdir) / "data.zarr"
+
+            # Set complex attrs
+            my_attrs = {
+                "string_key": "test_value",
+                "int_key": 123,
+                "float_key": 3.14,
+                "bool_key": True,
+                "list_key": [1, 2, 3],
+                "nested_dict": {
+                    "inner_key1": None,
+                    "inner_key2": 456,
+                    "nested_list": ["a", "b", "c"],
+                },
+            }
+            sdata = SpatialData()
+            sdata.attrs = my_attrs
+
+            # Write to disk with sdata_container_format
+            sdata.write(f, sdata_formats=sdata_container_format)
+
+            # Read back and verify attrs
+            sdata_read = read_zarr(f)
+            assert sdata_read.attrs == my_attrs
+
+    def test_attrs_incremental_write(
+        self,
+        sdata_container_format: SpatialDataContainerFormatType,
+    ) -> None:
+        """Test incremental write of attrs using write_attrs() and write_metadata()."""
+        with tempfile.TemporaryDirectory() as tmpdir:
+            f = Path(tmpdir) / "data.zarr"
+
+            # Initial write with attrs using sdata_container_format
+            initial_attrs = {"initial_key": "initial_value", "counter": 0}
+            sdata = SpatialData()
+            sdata.attrs = initial_attrs
+            sdata.write(f, sdata_formats=sdata_container_format)
+
+            # Verify initial attrs
+            sdata_read1 = read_zarr(f)
+            assert sdata_read1.attrs == initial_attrs
+
+            # Update attrs using write_attrs()
+            sdata_read1.attrs["counter"] = 1
+            sdata_read1.attrs["new_key"] = "new_value"
+            sdata_read1.write_attrs(sdata_format=sdata_container_format)
+
+            # Read back and verify updated attrs
+            sdata_read2 = read_zarr(f)
+            assert sdata_read2.attrs["counter"] == 1
+            assert sdata_read2.attrs["new_key"] == "new_value"
+            assert sdata_read2.attrs["initial_key"] == "initial_value"
+
+            # Update attrs using write_metadata()
+            sdata_read2.attrs["counter"] = 2
+            sdata_read2.attrs["another_key"] = "another_value"
+            sdata_read2.write_metadata(sdata_format=sdata_container_format)
+
+            # Read back and verify all attrs
+            sdata_read3 = read_zarr(f)
+            assert sdata_read3.attrs["counter"] == 2
+            assert sdata_read3.attrs["new_key"] == "new_value"
+            assert sdata_read3.attrs["another_key"] == "another_value"
+            assert sdata_read3.attrs["initial_key"] == "initial_value"
+
+
+def test_attrs_v1_to_v2() -> None:
+    """Test that attrs are preserved when converting from V01 to V02."""
+    with tempfile.TemporaryDirectory() as tmpdir:
+        f_v1 = Path(tmpdir) / "data_v1.zarr"
+        f_v2 = Path(tmpdir) / "data_v2.zarr"
+
+        # Set attrs and write with V01
+        my_attrs = {
+            "test_key": "test_value",
+            "counter": 1,
+            "nested": {"inner": "value"},
+        }
+        sdata = SpatialData()
+        sdata.attrs = my_attrs
+        sdata.write(f_v1, sdata_formats=FORMAT_V01)
+
+        # Read with V01
+        sdata_v1 = read_zarr(f_v1)
+        assert sdata_v1.attrs == my_attrs
+
+        # Write with V02
+        sdata_v1.write(f_v2, sdata_formats=FORMAT_V02)
+
+        # Read with V02 and verify attrs are preserved
+        sdata_v2 = read_zarr(f_v2)
+        assert sdata_v2.attrs == my_attrs