diff --git a/rest_framework_api_key/migrations/0005_auto_id.py b/rest_framework_api_key/migrations/0005_auto_id.py
new file mode 100644
index 0000000..dbb75ff
--- /dev/null
+++ b/rest_framework_api_key/migrations/0005_auto_id.py
@@ -0,0 +1,26 @@
+# Generated by Django 2.2.2 on 2019-06-29 11:49
+
+from django.db import migrations, models
+
+APP_NAME = "rest_framework_api_key"
+MODEL_NAME = "apikey"
+DEPENDENCIES = [(APP_NAME, "0004_prefix_hashed_key")]
+
+
+class Migration(migrations.Migration):
+
+    dependencies = DEPENDENCIES
+
+    operations = [
+        migrations.RemoveField(model_name=MODEL_NAME, name="id"),
+        migrations.AddField(
+            model_name=MODEL_NAME,
+            name="id",
+            field=models.AutoField(
+                auto_created=True,
+                primary_key=True,
+                serialize=False,
+                verbose_name="ID",
+            ),
+        ),
+    ]
diff --git a/rest_framework_api_key/models.py b/rest_framework_api_key/models.py
index 15cf50c..2736053 100644
--- a/rest_framework_api_key/models.py
+++ b/rest_framework_api_key/models.py
@@ -15,12 +15,8 @@ def assign_key(self, obj: "AbstractAPIKey") -> str:
             key, prefix, hashed_key = self.key_generator.generate()
         except TypeError:  # Compatibility with < 1.4
             key, hashed_key = self.key_generator.generate()
-            pk = hashed_key
             prefix, hashed_key = split(hashed_key)
-        else:
-            pk = concatenate(prefix, hashed_key)
 
-        obj.id = pk
         obj.prefix = prefix
         obj.hashed_key = hashed_key
 
@@ -63,9 +59,6 @@ class APIKeyManager(BaseAPIKeyManager):
 class AbstractAPIKey(models.Model):
     objects = APIKeyManager()
 
-    id = models.CharField(
-        max_length=100, unique=True, primary_key=True, editable=False
-    )
     prefix = models.CharField(max_length=8, unique=True, editable=False)
     hashed_key = models.CharField(max_length=100, editable=False)
     created = models.DateTimeField(auto_now_add=True, db_index=True)
diff --git a/tests/project/heroes/migrations/0003_auto_id.py b/tests/project/heroes/migrations/0003_auto_id.py
new file mode 100644
index 0000000..23193b4
--- /dev/null
+++ b/tests/project/heroes/migrations/0003_auto_id.py
@@ -0,0 +1,26 @@
+# Generated by Django 2.2.2 on 2019-06-29 11:49
+
+from django.db import migrations, models
+
+APP_NAME = "heroes"
+MODEL_NAME = "heroapikey"
+DEPENDENCIES = [(APP_NAME, "0002_prefix_hashed_key")]
+
+
+class Migration(migrations.Migration):
+
+    dependencies = DEPENDENCIES
+
+    operations = [
+        migrations.RemoveField(model_name=MODEL_NAME, name="id"),
+        migrations.AddField(
+            model_name=MODEL_NAME,
+            name="id",
+            field=models.AutoField(
+                auto_created=True,
+                primary_key=True,
+                serialize=False,
+                verbose_name="ID",
+            ),
+        ),
+    ]