The church in Koszewko was built of fieldstone on a rectangular plan in the 15th century, with a tower and presbytery. In 1709-1724 the church was reconstructed, there were added annexes to the presbytery and a chapel with a neo-Baroque crypt. The church has a Baroque, wooden altar from 1723 made by Jacob Howe and Heinrich Kockeritz. The pulpit altar is richly ornamented. The church tabernacle of 58 x 49 cm and 62 x 48 cm with a forged door and decorative hinges is situated in the western wall. In the church there is a wooden gallery preserved, made in 1723 by Jacob Howe and Heinrich Kockeritz. Four sandstone gravestones were placed in a nave recess by the southern wall.