The Church of St. Onuphrius in Oleszyce is a Greek Catholic temple that constitutes an important element of the region's sacral architecture. It was built in 1809 on a cruciform plan, which is typical for many churches of that period. A characteristic feature of the structure is its central dome and a small belfry, while the presbytery is triapsidal, giving the whole a harmonious appearance. On the sides of the church, there are two sacristies, a practical solution commonly found in religious buildings. The church underwent several renovations, including in 1901, when it was thoroughly rebuilt, and again in 1936. However, after World War II, in 1947, the building was abandoned, and in the 1950s, it began to be used as a warehouse. In the early 1970s, the masonry bell tower, built in 1846, was demolished. Today, the church lies in ruins, a sad testament to the transformations that took place in the region after the wars and social changes. The Church of St. Onuphrius is not only an example of interesting architecture but also a witness to the rich history and culture of Greek Catholics in Poland. It is worth noting that although it is currently in poor condition, it remains an important element of local cultural heritage, attracting the attention of architecture and history enthusiasts.