The paper analyses four altars made of stone and marble in the parish Church of St. Peter in Ilirska Bistrica. Stylistically and chronologically, their construction went through three phases during the eighteenth century. The oldest ones stand under the triumphal arch and may be dated to the first quarter of the eighteenth century. The altar on the left was originally dedicated to St. Nicholas, whose figure is carved on the altar frontal. It was the work of an unknown workshop influenced by the Pacassi family of altar builders from Gorizia. The sculptures were produced by an unknown local master who was familiar with the opus of Angelo De Putti, the travelling sculptor from Padua. On the right side of the triumphal arch, the Altar of the Blessed Sacrament was accomplished by an unknown master who drew inspiration from the works of the sculptor and altar builder Paolo Zuliani from Gradisca d’Isonzo. The most important of all, the marble altar was commissioned about 1741 from the Rijeka sculptor Antonio Michelazzi for the Chapel of the Blessed Virgin Mary of the Rosary, constructed shortly before that. Finally, a monumental new main altar was built about 1780 by the sculptors Sebastiano Petruzzi and Giovanni Battista Zipperla.