Mosaics is of the utmost significance in the decor of the Church of the Resurrection, forming one of the largest collections of monumental mosaics in Europe. Among the competitors for a commission to execute mosaics were the renowned Italian firms, such as the Venetian workshop of Antonio Salviatti and Societa Musiva, the German firm Puhl & Wagner, and the mosaic department of the Imperial Academy of Arts. The winner of the contest was Alexander and Vladimir Frolov workshop, a private company founded in 1890. From 1896 to 1907 its masters, skilled in the use of the reverse or venitician technique, assembled over 600 icons and mosaic images with the total area of 7056 sq. m. The sketches for mosaics were created by 32 painters, including Victor Vasnetsov, Mikhail Nesterov, Andrey Ryabushkin, Vasily Belyaev, and Nikolay Kharlamov.
Following the iconographic program of the cruciform and domed cathedrals dating from the 17th century, mosaic icons and ornaments fill up rhythmically the spaces of pillars and walls flowing into the curved surfaces of arches, vaults and dome ceilings.
The mosaics are arranged in line with the theological conception of a church. The dome ceiling is filled with the mosaic image of Christ the Pantocrator.
In the central part of the church, on the walls and vaults are depictions of scenes from the Holy Scripture, ranging from the Nativity to the Assumption of Christ. The dome pillars feature over 200 icons with images of church supporters – venerable men, martyrs and apostles. Engrossed in silent worship, they, like faithful sentries, watch over the divine history reflected in the mosaics. The special character of the church introduced some changes in the interior design. There are two focal points in the church: at the east end - the altar with a magnificent image of Christ and at the west end – the canopy over the assassination site with surrounding mosaic images on themes of Golgotha drama.
The iconographic program also reflects the local history through images of Russian saints, including the Prince of Vladimir from Kiev and the Princess Olga, the martyred princes Boris and Gleb, Mikhail of Chernigov, the nobleman Fedor, and Alexander Nevsky. The distinctive feature of mosaic decoration here is its colorful and unique ornaments. Following the iconography, they structure, enrich and reinforce the emotional perception of the church imagery.
The mosaics underwent restoration from 1980 to 1994. A team of restorers headed by mosaic artist and painter V.A. Shershnev cleared them, restored and recreated the lost fragments and, thus, revived the unique collection of Russian monumental mosaics dating from the late 19th - early 20th centuries.