Abstract: A coin testing apparatus for identifying non-circular coins of a particular denomination. The apparatus includes an array of coin presence sensors. Two reference sensors are located along a line perpendicular to the coin track equidistant above and below a line parallel to the track and approximately half the coin's mean diameter above the track. Two secondary sensors are located along the line parallel to the track so that when a coin of the said denomination first occludes one or other of the reference sensors it occludes one but not both of the secondary sensors. Other sensors are provided to indicate that the coin is non-circular.