The church was built only in 1903, and it was consecrated in honour of the Exaltation of the Holy Cross on December the10th same year.  In 1904, a new permanent priest Mr. Zimmerman moved to Korsze. The church in Korsze was granted the rights of the parish on February the 22nd, 1910.  Built in the neo-Gothic style, the church was very small (today’s presbytery).The church stood on a small hill and there were no stairs but a cobblestone road leading to it.

The increase in the number of baptisms and funerals recorded in the parish registers shows the increase of the population in Korsze. There appear some Polish names there too. These were probably Polish workers seeking work in Prussia. By the end of the 1930s, the church was too small for the faithful of Korsze, despite the fact that the most of the inhabitants were protestant. In 1939 a new priest Mr. Derra replaced priest Zimmerman, who left the parish together with the retreating German army in January 1945.

The fifties was a period of work on embellishing the church. There were newly cleaned walls and floor, main altar, processional banners, pews, confessionals and chasubles. The Korsze parish grew as more and more faithful arrived. The tiny church did not room everyone during the service despite the pews being added.

Having had the temple enlarged, on the 18th Oct.1959 the bishop Tomasz Wilczynski consecrated it. It was the first church consecration in Warmia region after the 2nd World War.

In 1962, a new floor made of terrazzo tiles was laid, and in 1965 a high altar chosen by the majority of parishioners was built. The renovation work in the church was interrupted by the sudden death of priest Lachowicz.  On December the 17th, 1967, a new priest Stefan Winiecki was appointed. He took over the parish on the 31st of March 1968 and continued embellishing of the church. The altar of Our Lady of Perpetual Help was consecrated in 1969 by the Bishop Jan Obłąk.