diff --git a/src/argus/incident/migrations/0004_incidentrelation_prevent_loop.py b/src/argus/incident/migrations/0004_incidentrelation_prevent_loop.py
new file mode 100644
index 000000000..7a18cb115
--- /dev/null
+++ b/src/argus/incident/migrations/0004_incidentrelation_prevent_loop.py
@@ -0,0 +1,18 @@
+# Generated by Django 3.2.5 on 2021-08-19 09:19
+
+from django.db import migrations, models
+import django.db.models.expressions
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('argus_incident', '0003_incident_level'),
+    ]
+
+    operations = [
+        migrations.AddConstraint(
+            model_name='incidentrelation',
+            constraint=models.CheckConstraint(check=models.Q(('incident1', django.db.models.expressions.F('incident2')), _negated=True), name='incidentrelation_prevent_loop'),
+        ),
+    ]
diff --git a/src/argus/incident/models.py b/src/argus/incident/models.py
index b02d8668f..f0fea63ca 100644
--- a/src/argus/incident/models.py
+++ b/src/argus/incident/models.py
@@ -359,6 +359,13 @@ class IncidentRelation(models.Model):
     type = models.ForeignKey(to=IncidentRelationType, on_delete=models.PROTECT, related_name="incident_relations")
     description = models.TextField(blank=True)
 
+    class Meta:
+        constraints = [
+            models.CheckConstraint(
+                check=~models.Q(incident1=models.F("incident2")), name="incidentrelation_prevent_loop"
+            ),
+        ]
+
     def __str__(self):
         return f"Incident #{self.incident1.pk} {self.type} #{self.incident2.pk}"