diff --git a/CHANGELOG.md b/CHANGELOG.md
index b6d676a1..4241e2f7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,9 @@
 ### New Checks
 
 * Added `check_rate_is_not_zero` for ensuring non-zero rate value of `TimeSeries` that has more than one frame. [#389](https://github.com/NeurodataWithoutBorders/nwbinspector/issues/389)
+* Added `check_electrical_series_conversion_factors` for ensuring non-default conversion/offset factors of any `ElectricalSeries` that has an integer data type. [#395](https://github.com/NeurodataWithoutBorders/nwbinspector/issues/395)
+
+
 
 # v0.4.30
 
diff --git a/src/nwbinspector/checks/ecephys.py b/src/nwbinspector/checks/ecephys.py
index 5044bd8d..d853993d 100644
--- a/src/nwbinspector/checks/ecephys.py
+++ b/src/nwbinspector/checks/ecephys.py
@@ -79,3 +79,16 @@ def check_spike_times_not_in_unobserved_interval(units_table: Units, nunits: int
                     "observed intervals."
                 )
             )
+
+
+@register_check(importance=Importance.CRITICAL, neurodata_type=ElectricalSeries)
+def check_electrical_series_conversion_factors(electrical_series: ElectricalSeries):
+    data = electrical_series.data
+    if (
+        np.issubdtype(data.dtype, np.integer)
+        and electrical_series.conversion == electrical_series.DEFAULT_CONVERSION
+        and electrical_series.offset == electrical_series.DEFAULT_OFFSET
+    ):
+        return InspectorMessage(
+            message="ElectricalSeries data type is integer and conversion factor and offset are both default, the value may not be in the correct unit"
+        )
diff --git a/tests/unit_tests/test_ecephys.py b/tests/unit_tests/test_ecephys.py
index ccd3ab63..3cd47f71 100644
--- a/tests/unit_tests/test_ecephys.py
+++ b/tests/unit_tests/test_ecephys.py
@@ -15,6 +15,7 @@
     check_electrical_series_dims,
     check_electrical_series_reference_electrodes_table,
     check_spike_times_not_in_unobserved_interval,
+    check_electrical_series_conversion_factors,
 )
 
 
@@ -155,6 +156,76 @@ def test_trigger_check_electrical_series_reference_electrodes_table(self):
             == "electrodes does not  reference an electrodes table."
         )
 
+    def test_check_electrical_series_dtype_pass(self):
+        electrodes = self.nwbfile.create_electrode_table_region(region=[0, 1, 2, 3, 4], description="all")
+
+        electrical_series = ElectricalSeries(
+            name="elec_series",
+            description="desc",
+            data=np.ones((100, 5), dtype=np.dtype("float64")),
+            electrodes=electrodes,
+            rate=30.0,
+        )
+
+        self.nwbfile.add_acquisition(electrical_series)
+
+        assert check_electrical_series_conversion_factors(electrical_series) is None
+
+    def test_check_electrical_series_dtype_fail(self):
+        electrodes = self.nwbfile.create_electrode_table_region(region=[0, 1, 2, 3, 4], description="all")
+
+        electrical_series = ElectricalSeries(
+            name="elec_series",
+            description="desc",
+            data=np.ones((100, 5), dtype=np.dtype("int16")),
+            electrodes=electrodes,
+            rate=30.0,
+        )
+
+        self.nwbfile.add_acquisition(electrical_series)
+
+        assert check_electrical_series_conversion_factors(electrical_series) == InspectorMessage(
+            message=(
+                "ElectricalSeries data type is integer and conversion factor and offset are both default, the value may not be in the correct unit"
+            ),
+            importance=Importance.CRITICAL,
+            check_function_name="check_electrical_series_dtype",
+            object_type="ElectricalSeries",
+            object_name="elec_series",
+        )
+
+    def test_check_electrical_series_dtype_non_default_conversion_skip(self):
+        electrodes = self.nwbfile.create_electrode_table_region(region=[0, 1, 2, 3, 4], description="all")
+
+        electrical_series = ElectricalSeries(
+            name="elec_series",
+            description="desc",
+            data=np.ones((100, 5), dtype=np.dtype("int16")),
+            electrodes=electrodes,
+            rate=30.0,
+            conversion=0.1,
+        )
+
+        self.nwbfile.add_acquisition(electrical_series)
+
+        assert check_electrical_series_conversion_factors(electrical_series) is None
+
+    def test_check_electrical_series_dtype_non_default_offet_skip(self):
+        electrodes = self.nwbfile.create_electrode_table_region(region=[0, 1, 2, 3, 4], description="all")
+
+        electrical_series = ElectricalSeries(
+            name="elec_series",
+            description="desc",
+            data=np.ones((100, 5), dtype=np.dtype("int16")),
+            electrodes=electrodes,
+            rate=30.0,
+            offset=0.1,
+        )
+
+        self.nwbfile.add_acquisition(electrical_series)
+
+        assert check_electrical_series_conversion_factors(electrical_series) is None
+
 
 def test_check_spike_times_not_in_unobserved_interval_pass():
     units_table = Units(name="TestUnits")