In the early years of the facility the majority of collections were humble folk monuments of material and spiritual culture. Fundamental changes in the functioning of the Museum brought only 1975, when as a result of transformation of the country, the White Podlasie became the seat of provincial authorities. Increased budget facility zaprocentował significant increase in collections, began to form the first collections. In 1975, he entered in the inventories of museum objects was only in 2116, but already in 1982 the Museum collections numbered about 17 000 units, and in 1990 their number increased to 21 000 exhibits.
Thanks purchases formed a thematic collection of Polish painting called "Horses, riders, teams in Polish painting of the century". National air painting in Janow Podlaski organized regularly in the years 1975-1998 resulted in a significant collection of contemporary painting. Gathered substantial numismatic and medal. Systematically enlarged historical collections, gathering documents, archives, and other items related to the past of the city and the region. Field studies and numerous competitions of folk art have contributed to the steady growth of the ethnographic collections.
In the years 1980-1995, mainly due to customs confiscation, gathered numbering about 1,400 objects, and therefore one of the largest collection of Russian icons XVII-XIX century. The collection department of history of art and valuable gifts to family hit Alexander Próchnicki, Bialski painter, architect and regionalist and numerous documents, photographs and old memorabilia, donated by Professor Stefan Kryński of Gdansk. In 1995, he obtained the legacy of the famous painter of the artistic output of Dabrownica Little Basil Albiczuka, and in 2005 a substantial deposit Bialskie paintings and prints by Zbigniew Karpinski, a professor of Fine Arts in Wroclaw. Valuable contribution to enriching the iconography of the city brought acquired in 2006, the work of Tadeusz Różyckiego Bialski watercolorist, sacrificed on the occasion of the organization of the exhibition by the artist's nephew, Professor. Kiejstut Bereźnicki, and Janusz Kulawca and Danuta Dunajko Andrzejuk. Now, after 40 years of operation of the institution, the number of collections of the Museum of Southern Podlasie in the White Podlasie is about 40 000 exhibits.