Located on the top of Sobornaya Gora is the beautiful Dormition Cathedral which is the eparchial cathedral of the Smolensk and Vyzama Eparchy. The construction of the original version of the cathedral was started in 1101 by Prince Vladimir Monomakh and completed by Prince Rostislav Mstistlavich of Smolensk in 1150. During the Time of Troubles and the siege of Smolensk, the cathedral was blown up with civilians inside; it is not known whether this was a deliberate case of mass-suicide or an accident. The top half of the cathedral was damaged in the explosion and in 1674, after the city had been returned to Russia, it was decided to completely knock down the cathedral and built it again. Work was started in 1677 and after many setbacks it was finally completed in 1772, almost 100 years later.

As beautiful as it is on the outside the cathedral is even more stunning inside which is decorated by a huge glittering golden five-tier iconostasis. Previously the revered Our Lady of Smolensk Icon was housed here but the icon was lost in 1941 during the Nazi occupation.