diff --git a/homeassistant/components/onvif/base.py b/homeassistant/components/onvif/base.py
index cca84c4562a..ab41fcc8f29 100644
--- a/homeassistant/components/onvif/base.py
+++ b/homeassistant/components/onvif/base.py
@@ -28,17 +28,17 @@ class ONVIFBaseEntity(Entity):
             "model": self.device.info.model,
             "name": self.device.name,
             "sw_version": self.device.info.fw_version,
+            "identifiers": {
+                # MAC address is not always available, and given the number
+                # of non-conformant ONVIF devices we have historically supported,
+                # we can not guarantee serial number either.  Due to this, we have
+                # adopted an either/or approach in the config entry setup, and can
+                # guarantee that one or the other will be populated.
+                # See: https://github.com/home-assistant/core/issues/35883
+                (DOMAIN, self.device.info.mac or self.device.info.serial_number)
+            },
         }
 
-        # MAC address is not always available, and given the number
-        # of non-conformant ONVIF devices we have historically supported,
-        # we can not guarantee serial number either.  Due to this, we have
-        # adopted an either/or approach in the config entry setup, and can
-        # guarantee that one or the other will be populated.
-        # See: https://github.com/home-assistant/core/issues/35883
-        if self.device.info.serial_number:
-            device_info["identifiers"] = {(DOMAIN, self.device.info.serial_number)}
-
         if self.device.info.mac:
             device_info["connections"] = {
                 (CONNECTION_NETWORK_MAC, self.device.info.mac)