The interior of the cathedral reflects its priority and many-sided importance: it was the seat of the Bishop and - in 1299-1328 - the Metropolitan of the Russian Orthodox Church, it was the spiritual and artistic center of the Grand Principality.

The nucleus of the interior with its high central dome, 6 pillars and a choir gallery (i.e. an inner balcony in the western part of the church) belongs to the building commissioned by Prince Andrei Bogolyubsky and constructed in 1158-1161, outer galleries with 4 smaller domes were added after the fire of 1185, during the reign of Prince Vsevolod the Big Nest. From the very beginning the cathedral kept the most sacred possession of the principality - a miracle-working Vladimir icon of the Mother of God. The icon came to Russia from Byzantium and was brought by Prince Andrei from Kiev to Vladimir in 1157. It was created in the 12th century, but it is believed that the initial image was painted by Apostle Luke who portrayed Virgin Mary herself. In the 15th century the icon was moved to Moscow and it is kept in the St Nicholas Church at the Tretyakov Gallery now.

The cathedral was a scriptorium and had a rich library. It also served as a burial place for many princes and members of their families (the tombs are in the northern and central parts of the cathedral), as well as for bishops and priests (buried in the southern gallery).

Frescoes of the Assumption Cathedral are of exceptional artistic value. Fragments of the original paintings of 1161 (two saints with scrolls in their hands, peacocks and ornaments) are on the northern wall of the cathedral built by Prince Andrei. Bright flowers (lilies) were painted in 1189 on the vault, under the choir gallery.

The Assumption Cathedral is the only place where frescoes by Andrei Rublev and Daniil Chorny (1408) could survive (more then 300 sq. m). Compositions of the Last Judgement, the Unfailing Light and the Abraham’s Bosom were painted on the vault, under the choir gallery.

Some other compositions survived partially on the upper vault of the cathedral: the Descent of the Holy Spirit, the Transfiguration, the Presentation of the Holy Virgin, the Offering of St Joahim and St Anna.

Being a younger contemporary of St. Sergius of Radonezh and Prince Dmitry Donskoi Andrei Rublev could comprehend the spiritual upsurge of the Russian society in the 15th century and convey in colors and biblical images Russia's readiness to fight against the Mongol yoke. The faces of saints in his icons and frescoes are illuminated with joy and love. The Rublev's frescoes themselves are as radiant as haloes of saints.

In the eastern part of the church opposite the choir gallery, separating the altar, rises a magnificent iconostasis, built on donations of Catherine II in 1774 - gilded wood carving in splendid "baroque" forms, icons, created in the manner of secular painting, royal door with the unusual sculptured Annunciation on it.

The interior - its frescoes, iconostasis, tombs, etc.- has been restored many times.

The Assumption Cathedral has always been the principal Cathedral of the diocese; only in 1927-1944 it was not used as a working church.

Today the interior is used by both the Russian Orthodox Church and the Vladimir and Suzdal museum.