The permanent exhibition of the Gacka Museum consists of six units, which features artifacts from six different museum collections. Items from the Archaeological Collection, the Stojan Aralica Memorial Collection, the Art Collection, and the Historical Collection are kept in four units on the ground level of the building. The basement of the building includes the fifth section of the permanent exhibition, which features pieces from the Ethnographic Collection. Heritage in Disappearance: The Otočac Brewery, which concludes the Gacka Museum's permanent exhibition, features several exhibits from the Cultural and Historical Collection.

The first section of the Gacka Museum's permanent exhibition features about 300 artifacts from the Archaeological Collection. The items on display span from the Bronze Age to the Middle Ages and are from many historical eras. The primary artifacts that attest to the first residents of Gacka are jewelry, dishes, tools, and weapons made of bronze, pottery, amber, wood, glass, glass paste, stone, and bones, but there are also other items that attest to subsequent habitation.

Items from the Memorial Collection of Stojan Aralica form the second part of the Gacka Museum's permanent exhibition. It exhibits about a hundred items that their owner, Stojan Aralica, donated to the town of Otočac in 1976. In addition to his works - oils, watercolors, pastels and pencil, charcoal and ink drawings - photographs, painting accessories, documents, awards, publications and other personal belongings of Aralica are also exhibited.

The third section of the Gacka Museum's permanent display features the writings of twelve authors with various stylistic and thematic tendencies. The exhibited works belong to the Fine Art Collection, one of the Museum's six collections. The works exhibited in this collection were created during the second half of the 20th century, and belong to authors who exhibited individually or collectively in the Gacke Museum, but also to authors who participated in Art Colonies between 2003 and 2010.

The fourth unit of the Gacka Museum's permanent exhibition features a portion of the Historical Collection's artifacts. These are objects that bear witness to events from the period of the Croatian war of Independence, which lasted from 1991 to 1995 and in which Otočac and some surrounding settlements found themselves on the front line of defense.

The fifth section of the Gacka Museum's permanent exhibition, located in the basement, exhibits the objects of the Ethnographic Collection through a depiction of the traditional life, everyday life and customs of the inhabitants of Gacka from the first half of the 20th century. metal is exhibited in three smaller complementary units, the aim of which is to present different segments of village life and present the wealth of all kinds of life practices that remained in Gacka until the 50s of the 20th century.

The cultural-historical collection of the Gacka Museum consists of objects of social, historical, artistic and/or scientific significance - memorials, old machines, furniture, old school supplies, photographs, printed matter and postcards. Part of the cultural-historical collection is on display as part of the permanent exhibition Heritage in Disappearance: The Otočac Brewery, which is located on the first floor of the building as the last part of the permanent exhibition.