''Slava'' is celebrated on the day when the Serbian Orthodox Church commemorates a specific saint, which is the 27th of October in the case of Saint Petka. Among the Serbs, Saint Nicholas (the 19th of December), Saint John the Baptist (the 20th of January), Saint Michael the Archangel (the 21st of November), Saint George (the 6th of May) and Saint Petka are most often celebrated. As a rule ''slava'' is passed down from father to eldest son, and it rarely happens that someone changes the patron saint. Saint Petka is an exception from this rule because she is mostly celebrated by those whom she has helped. It often happens that Saint Petka is the second saint of a family that already has one, but because she helped a family member, she is also celebrated as a sign of gratitude.

Worshipers of Holy Petka always fast on Fridays, because they consider that to be her day. Fasting ends with Holy Communion, which has a special significance when received on Petka's Day - the 27th of October.