In the southwestern part of the monastery is the Smolensk Church, a unique monument of Kostroma architecture from the 19th century, built in the Russian-Byzantine style. Its structure includes a fragment of the old monastery fence from the 17th century with a corner fortress tower. After the fire of 1773, a wooden chapel was added to the tower. In 1824-1825, funded by Kostroma merchant F.M. Obryadchikov, likely according to the design of provincial architect P.I. Fursov, the Smolensk Church was built in place of the chapel, with the tower as its foundation. In 1827, the church was expanded to the north and east with apse extensions. After the fires of 1840 and 1847, it was connected in the 1860s to the hospital building, and after the fire of 1887, it was restored in 1888-1891 with updated facade and interior finishes. Inside, the dome of the church was decorated with paintings, the walls with artificial marble, and the floors and stairs were made of Portland cement with marble chips. From 1972 to 1978, the building was restored by KSNRPM.

The church, two-storied, column-free, and single-domed, is made of brick and plastered, representing a high square structure surrounded on three sides by slightly lowered extensions with apses. The base of the square is the corner tower of the fence, whose massive walls are clearly visible in the building's plan. Each wall ends with three false zakomaras. Above the domed roof rises a faceted drum with a gilded head and cross. The Byzantine architectural style is emphasized by striped facades with wide rustication, the rustication of the archivolts of the arched windows and zakomaras, as well as relief Greek crosses in the tympana of the lower windows and on the apses. The entrances are adorned with iron double-leaf grilles with plant-geometric ornamentation. Inside, the upper floor of the temple is covered by an eight-vaulted arch with corner trompes and an opening for the drum. From the interior decoration, only the revered Smolensk Icon of the Mother of God, considered miraculous, has survived, painted no earlier than the mid-17th century on a plaster base in a kiot embedded in the wall of the corner tower. The icon, exposed to rain and wind, as well as fires, has been restored multiple times. In the 18th century, the chapel added to the tower protected the icon from external influences. Inspections have shown that the painting of the icon is significantly deteriorated, down to the preparatory layer.