The unique and original Pomor book-handwriting style, created by the scribes of the Vygo-Leksinsky community, was also widespread in the regional Old Believer centers of the Priestless denominations, including part of the Ural Old Believer settlers. The Depository of Ancient Manuscripts of the Ural Federal University contains manuscripts with Pomor decor collected during archaeographical expeditions in the Ural region and adjacent territories. The article examines development of Pomor handwritten ornamental decoration forms using the example of manuscripts of the LAS UrFU from the 18th to the beginning of the 20th centuries. The process of the formation of the style basis (1st half — mid-18th century), the acquisition of its classical appearance (2nd half of the 18th c.), the process of evolution of individual elements, which led to changes and variability in compositions while maintaining repeatable stable forms, are traced (1st half of the 19th c.). The author also notes the trend of “fading” of the style, due to changes of a socio-political and cultural nature — the dissolution of the Vyg monastery and cessation of the creation of literary artefacts in a centralized manner, the spread of the practice of private scribing and design of manuscripts, as well as the influence of the so-called urban culture on the art of manuscript design, and regional features of writing, elements of folk arts and crafts (2nd half of 19th — early 20th cc.). The study of the forms of Pomor book ornament was carried out on the basis of methods of working with the decor of Pomor handwritten books developed by St. Petersburg scientists G. V. Markelov and F. V. Panchenko, including descriptions of the main types, varieties, subspecies of particular pattern elements, compiling alphanumeric designations of the main designs of Pomor ornament, distinguishing the features of compositions characteristic of a certain period of time, as well as problems of transformation of elements and style interpretation variants. The use of this technique allowed taking a fresh look at the problem of the existence and development of the Pomor style as a stable structure. Having created an ornamental style unique in its beauty and expressiveness, the scribes of the Vyg Pustyn produced manuscripts with characteristic Pomor decor for more than a century and a half. However, even after the liquidation of the monasteries and the dispersal of workshops for copying manuscripts (middle of the 19th century), the Pomor style continued to live in the manuscripts of the Old Believers due to its relevance. The stability, repeatability of designs and their immutability within the cultural and historical community of the Old Believer population allows speaking of the Pomor style as a bright independent phenomenon of book design art and a phenomenon of a historical and cultural nature.