In the early years of the majority of the institutions were modest collections of monuments of folk material and spiritual culture. Fundamental changes in the functioning of the Museum has brought only a year in 1975, when as a result of transformation of the country, Biala Podlaska became the seat of the provincial government. Increased budget establishments paid off a significant increase in collections, began to form the first collections. In 1975 he entered the museum inventories were only 2116 objects, but already in 1982 the Museum collections consisted of about 17 000 units, and in 1990 their number increased to 21 000 exhibits.
With purchases formed a thematic collection of Polish painting called "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. Accumulated substantial numismatic and medalist. Systematically enlarged historical collections, gathering documents, archives, and other items related to the past of the city and the region. Field studies and numerous folk art competitions have contributed to the steady growth of the ethnographic collection.
In the years 1980-1995, mainly due to the customs confiscations, gathered numbering about 1,400 objects, and so one of the biggest collection of Russian icons XVII-XIX century. The collection of history and art department hit precious gifts the family of Alexander Próchnicki, Bialski painter, architect and regionalist and numerous documents, photographs and old memorabilia, donated by Professor Stefan Kryński from Gdansk. In 1995 he obtained the legacy of the creative achievements of the famous painter of Dąbrowicy Little Basil Albiczuka, and in 2005 a significant deposit Bialskie paintings and prints by Zbigniew Karpinski, 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, offered on the occasion of the organization of the exhibition by the artist's nephew prof. Kiejstut Bereźnicki and Janusz cripple and Danuta Dunajko Andrzejuk. Now, after 40 years of operation of the institution, the number of collections of the Museum of Southern Podlasie in Biala Podlaska is about 40 000 exhibits.