A geochronological and geochemical study on 10 samples of seafloor massive sulfides (SMS) from the inactive Peterburgskoye hydrothermal field at the Mid-Atlantic Ridge (MAR) was carried out. The 230Th/U ages of the SMS are the oldest ever found in other fields at the MAR. According to them the SMS formed from ca. 170 to 63 ka. Their possible spatial evolution was proposed. The oldest hydrothermal ores from the Peterburgskoye field consist mainly of pyrite and chalcopyrite and have geochemical properties typical for SMS associated with basalts.