Saint Petka’s log-cabin church in Koštunići is located on a hill above the centre of the village, on a cemetery. Before it was built, townsmen would gather at the big oak tree, which was close to the church. It is considered that it was constructed in the first half of the XIX century, but the exact year hasn’t been established yet. According to the type, it is one of the smallest log-cabin churches in Serbia, with its total surface of 40 m². It is rectangular in shape and built in a traditional way by placing oak planks on a stone foundation. Then, walls were formed by using logs joined together with a dovetail system and with the help of pillars. The east part of the building has a semi-circular altar divided into four sections, which made a polygonal apse on the outside. The roof of the church is not high. It is covered in tiles, round in shape above the apse, and flat above the west entrance section.

When it comes to architecture, the church is built in a simple way without any particular decoration. Only the main portal has some ornaments. The interior of the temple contains an altar wood partition. On the iconostasis, there is a wooden painted cross with barely visible traces of Crucifixion, which yet testifies of a painter being one of the better ones of his time. Based on the traces in the interior, one can come to the conclusion that there used to be a narthex in the church itself. The west part of the church has a flat ceiling, and there are no traces that it used to be arched.