The church has national recognition and statutory protection from alteration as it has been designated as a Grade II* listed building – the second-highest of the three grades of listing, designating "particularly important buildings of more than special interest". It was given this status on 30 January 1968, and has been listed because it is regarded as "a good example of a simple, substantially unaltered, late Medieval church." Cadw (the Welsh Government body responsible for the built heritage of Wales and the inclusion of Welsh buildings on the statutory lists) also notes that many old churches in Anglesey were rebuilt or restored during the 19th century, and that St Mary's "can be considered an important survival."
