The section Modern history of Bulgaria deals with the study and popularisation of the history of the II World War. As a result of the collection work there have been filed and preserved in the basic fund of the museum original materials, photographs and documents in the following collections:

- the participation of the regiments of Sliven in the final phase of the II World War
- youth-brigade movement (1946-1951)
- samples of the products of the industrial plants and firms
- the district of Sliven and its twin towns in Germany, the Ukraine, Poland and Hungary
- cultural life in the Sliven district
- the activities of the opposition in the region of Sliven (1944-1954)
- books by authors from Sliven