diff --git a/tailbone/views/tempmon/probes.py b/tailbone/views/tempmon/probes.py
index aed366da..bf2ede82 100644
--- a/tailbone/views/tempmon/probes.py
+++ b/tailbone/views/tempmon/probes.py
@@ -28,10 +28,23 @@ from __future__ import unicode_literals, absolute_import
 
 from rattail_tempmon.db import model as tempmon
 
+import formalchemy as fa
+
 from tailbone import forms
+from tailbone.db import TempmonSession
 from tailbone.views.tempmon import MasterView, ClientFieldRenderer
 
 
+def unique_config_key(value, field):
+    probe = field.parent.model
+    query = TempmonSession.query(tempmon.Probe)\
+                   .filter(tempmon.Probe.config_key == value)
+    if probe.uuid:
+        query = query.filter(tempmon.Probe.uuid != probe.uuid)
+    if query.count():
+        raise fa.ValidationError("Config key must be unique")
+
+
 class TempmonProbeView(MasterView):
     """
     Master view for tempmon probes.
@@ -63,6 +76,7 @@ class TempmonProbeView(MasterView):
             readonly=True)
 
     def _preconfigure_fieldset(self, fs):
+        fs.config_key.set(validate=unique_config_key)
         fs.client.set(label="TempMon Client", renderer=ClientFieldRenderer)
         fs.appliance_type.set(renderer=forms.renderers.EnumFieldRenderer(self.enum.TEMPMON_APPLIANCE_TYPE))
         fs.status.set(renderer=forms.renderers.EnumFieldRenderer(self.enum.TEMPMON_PROBE_STATUS))