In the early years of the facility predominant part of meager harvests were monuments of folk material and spiritual culture. Fundamental changes in the functioning of the Museum brought only a year in 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 were about 17 000 units, and in 1990 their number increased to 21 000 exhibits.
Thanks purchases formed a thematic collection of Polish paintings under the name of "Horses, riders, teams in Polish painting of the century." Nationwide 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 was expanded historical collections, gathering documents, archives, and other items related to the past of the city and the region. Field studies and numerous competitions, folk art contributed to the steady growth of the ethnographic collection.
In the years 1980-1995, mainly due to customs confiscation, gathered the approximately 1,400 objects, and thus one of the largest collection of Russian icons XVII-XIX century. The collection department of art history and family hit precious gifts of 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 creative achievements of well-known painter of Dąbrownica Little Basil Albiczuka, and in 2005 a significant deposit Bialskie images and graphics 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 watercolorist Bialski Tadeusz Rozycki, sacrificed on the occasion of the organization of the exhibition by the artist's nephew prof. Kiejstut Bereźnicki, and Janusz Kulawca and Danuta Dunajko Andrzejuk. Now, after 40 years of the institution, the number of collections of the Museum of Southern Podlasie in the White Podlasie is about 40 000 exhibits.