The Apaturia was a festival with chiefly a social content, overshadowing the religious content. It was put on yearly, the raison d'etre being the registration of the young men of Athens on the citizen lists. The name implies the celebration of a "common paternity", inasmuch as all male members of the phratriae were descended from a common ancestor. It has not been established whether there was a parallel procedure for young girls; however, when a girl got married, the phratria she belonged to very often made a sacrifice at the Apaturia.

The festival took place in the month Pyanepsion (in other words, October). It lasted at least three days. The date on which it started was not fixed and constant, however, since this depended on the phratriae who were to organize it. Essentially the Apaturia was a festival which all the phratriae attended and took part in. But each phratria separately would organize the festival on a different day of Pyanepsion, depending on circumstances and its own tradition.

The name given to the first day of the festival was Dorpeia, since it involved the gathering of the members of the phratria for a shared banquet (dorpon). This took place at the house of one of the kinsfolk. The second day was named Anarrhysis (pulling back), the noun denoting the ritual slaying of a female goat or sheep which took place in honour of the phratria's protector deity (normally Zeus Phratrios or Athena Phratria). The third day was named Cureotis. It was on this day that new members were received into the phratria. The reason for the name may be either that it was kouroi who were introduced, or that there was the custom of snipping the child's hair before the ritual. The received child's parents brought the phratores a meion - a sheep or goat for the slaughter. If the boys were of advanced age, the sacrifice was known as koureion. During their ephebe years, young men were brought before the phratria a second time: the object of this was for them to complete their status as phratria members.