Aphnaeum (Ancient Greek: Αφναιον, Aphnaion) was an ancient city and former bishopric in Egypt.
It is currently a Latin Catholic titular see.
Its location is believed to be near the ruins of modern Tell-Defenneh.
Aphnaeum was important enough in the Egyptian Roman province of Augustamnica Secunda to become a suffragan bishopric of the Metropolitan of provincial capital Pelusium, but it faded with the town.
It is vacant, having had only two incumbents, both of the lowest (episcopal) rank :