diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7bb0cc59700172b87d2c824b06c553b00355c832..51ea93d60cf74636d38709b0b9b11763f2bc739f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed ###
 
+- #90 compare_entities function in apiutils does not check units
+
 ### Security ###
 
 ## [0.6.1] - 2021-12-03 ##
diff --git a/src/caosdb/apiutils.py b/src/caosdb/apiutils.py
index 21a8cc7ca700a8b119786dbef082db286ead5d57..4ee0dacd0ecf0a9e347866965786fb619dd7a725 100644
--- a/src/caosdb/apiutils.py
+++ b/src/caosdb/apiutils.py
@@ -637,6 +637,11 @@ def compare_entities(old_entity: Entity, new_entity: Entity):
                 newdiff["properties"][prop.name]["datatype"] = \
                     matching[0].datatype
 
+            if (prop.unit != matching[0].unit):
+                olddiff["properties"][prop.name]["unit"] = prop.unit
+                newdiff["properties"][prop.name]["unit"] = \
+                    matching[0].unit
+
             if (prop.value != matching[0].value):
                 olddiff["properties"][prop.name]["value"] = prop.value
                 newdiff["properties"][prop.name]["value"] = \
diff --git a/unittests/test_apiutils.py b/unittests/test_apiutils.py
index 717595d049a5a7c27b644dc6079d02efa1cefb71..9cf9e1b7ac0043f3c256f1210272ff15b9df458b 100644
--- a/unittests/test_apiutils.py
+++ b/unittests/test_apiutils.py
@@ -144,3 +144,38 @@ def test_compare_entities():
 
     assert "tests_234234" in diff_r1["properties"]
     assert "tests_TT" in diff_r2["properties"]
+
+    
+def test_compare_entities_units():
+    r1 = db.Record()
+    r2 = db.Record()
+    r1.add_parent("bla")
+    r2.add_parent("bla")
+    r1.add_parent("lopp")
+    r1.add_property("test", value=2, unit="cm")
+    r2.add_property("test", value=2, unit="m")
+    r1.add_property("tests", value=3, unit="cm")
+    r2.add_property("tests", value=45, unit="cm")
+    r1.add_property("tester", value=3)
+    r2.add_property("tester", )
+    r1.add_property("tests_234234", value=45, unit="cm")
+    r2.add_property("tests_TT", value=45, unit="cm")
+
+    diff_r1, diff_r2 = compare_entities(r1, r2)
+
+    assert len(diff_r1["parents"]) == 1
+    assert len(diff_r2["parents"]) == 0
+    assert len(diff_r1["properties"]) == 4
+    assert len(diff_r2["properties"]) == 4
+
+    assert "tests" in diff_r1["properties"]
+    assert "tests" in diff_r2["properties"]
+
+    assert "tester" in diff_r1["properties"]
+    assert "tester" in diff_r2["properties"]
+
+    assert "tests_234234" in diff_r1["properties"]
+    assert "tests_TT" in diff_r2["properties"]
+
+    assert diff_r1["properties"]["test"]["unit"] == "cm"
+    assert diff_r2["properties"]["test"]["unit"] == "m"