In modern Omsk, one of the main attractions is the ancient Nicholas Cossack Cathedral, founded on May 15, 1833. Its construction lasted ten years, and the solemn consecration took place three years before all the work was completed. The main funds for the construction of the cathedral were provided by Siberian Cossacks, but other residents of Omsk also contributed. The appearance of the new church was a true celebration for the townspeople. The cathedral had three parishes, the main one consecrated in honor of Nicholas the Wonderworker.

In addition to holding services, the cathedral became a center of public life. Since 1894, a four-grade school for girls operated here. The main relic of the cathedral was the banner of Ataman Yermak, but it disappeared during the Civil War. According to one version, the white ataman Annenkov stole it from the Reds, but the true fate of the banner is unknown. The church faced persecution from the Bolsheviks and was closed. In 1928, the building was handed over to the state and used for various purposes. Unique bells were taken away, the iconostasis was destroyed, and a cinema was placed in the cathedral. Later, a children's choir studio and a warehouse were located there. Over half a century, the Soviet government brought the building to a terrible state, and only the activity of the townspeople saved it from demolition.

In June 1998, the cathedral was returned to the faithful and restored. It now houses a copy of the banner of Ataman Yermak, a new iconostasis, and the relics of saints. The building has been renovated, and the church has once again become one of the most beautiful in Siberia.