diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8091b53ef437..7800f0fc6bb7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,7 +19,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - TDB
 
 ### Fixed
-- TDB
+- \[SDK\] Ability to create attributes with blank default values
+  (<https://github.com/opencv/cvat/pull/6454>)
 
 ### Security
 - TDB
diff --git a/cvat/apps/engine/migrations/0073_alter_attributespec_default_value_and_more.py b/cvat/apps/engine/migrations/0073_alter_attributespec_default_value_and_more.py
new file mode 100644
index 000000000000..7bfe361c875b
--- /dev/null
+++ b/cvat/apps/engine/migrations/0073_alter_attributespec_default_value_and_more.py
@@ -0,0 +1,22 @@
+# Generated by Django 4.2.1 on 2023-07-10 15:57
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("engine", "0072_alter_issue_updated_date"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="attributespec",
+            name="default_value",
+            field=models.CharField(blank=True, max_length=128),
+        ),
+        migrations.AlterField(
+            model_name="attributespec",
+            name="values",
+            field=models.CharField(blank=True, max_length=4096),
+        ),
+    ]
diff --git a/cvat/apps/engine/models.py b/cvat/apps/engine/models.py
index 5e9f6781eb2c..8b1ee700271f 100644
--- a/cvat/apps/engine/models.py
+++ b/cvat/apps/engine/models.py
@@ -881,8 +881,8 @@ class AttributeSpec(models.Model):
     mutable = models.BooleanField()
     input_type = models.CharField(max_length=16,
         choices=AttributeType.choices())
-    default_value = models.CharField(max_length=128)
-    values = models.CharField(max_length=4096)
+    default_value = models.CharField(blank=True, max_length=128)
+    values = models.CharField(blank=True, max_length=4096)
 
     class Meta:
         default_permissions = ()
diff --git a/cvat/apps/engine/serializers.py b/cvat/apps/engine/serializers.py
index a92df38a0a22..f3303ea0ab03 100644
--- a/cvat/apps/engine/serializers.py
+++ b/cvat/apps/engine/serializers.py
@@ -214,7 +214,7 @@ class Meta:
 
 class AttributeSerializer(serializers.ModelSerializer):
     values = serializers.ListField(allow_empty=True,
-        child=serializers.CharField(max_length=200),
+        child=serializers.CharField(allow_blank=True, max_length=200),
     )
 
     class Meta:
diff --git a/cvat/schema.yml b/cvat/schema.yml
index 47a68af2e933..cbb4310c538e 100644
--- a/cvat/schema.yml
+++ b/cvat/schema.yml
@@ -5993,7 +5993,6 @@ components:
             type: string
             maxLength: 200
       required:
-      - default_value
       - input_type
       - mutable
       - name
@@ -6011,16 +6010,13 @@ components:
           $ref: '#/components/schemas/InputTypeEnum'
         default_value:
           type: string
-          minLength: 1
           maxLength: 128
         values:
           type: array
           items:
             type: string
-            minLength: 1
             maxLength: 200
       required:
-      - default_value
       - input_type
       - mutable
       - name
diff --git a/tests/python/sdk/test_projects.py b/tests/python/sdk/test_projects.py
index 74ecf5e69084..852a286fc288 100644
--- a/tests/python/sdk/test_projects.py
+++ b/tests/python/sdk/test_projects.py
@@ -115,6 +115,30 @@ def test_can_create_empty_project(self):
         assert project.id != 0
         assert project.name == "test project"
 
+    def test_can_create_project_with_attribute_with_blank_default(self):
+        project = self.client.projects.create(
+            spec=models.ProjectWriteRequest(
+                name="test project",
+                labels=[
+                    models.PatchedLabelRequest(
+                        name="text",
+                        attributes=[
+                            models.AttributeRequest(
+                                name="text",
+                                mutable=True,
+                                input_type=models.InputTypeEnum("text"),
+                                values=[],
+                                default_value="",
+                            )
+                        ],
+                    )
+                ],
+            )
+        )
+
+        labels = project.get_labels()
+        assert labels[0].attributes[0].default_value == ""
+
     def test_can_create_project_from_dataset(self, fxt_coco_dataset: Path):
         pbar_out = io.StringIO()
         pbar = make_pbar(file=pbar_out)