The collection of two-winged insects (mosquitoes and flies) contains over 60000 specimens in about 120 entomological boxes. The first materials were collected before 1900 by Meunier, Nedelkov and Joakimoff. A large number of specimens (of economic importance and parasitic forms) were collected by P. Tschorbadjiew. The materials collected by N. Nedelkov include most families. P. Drensky has been working on the two-winged insects for the longest time. Most of the materials of the exhibition belong to him. A. Drenowsky had been working on the mosquito dipterans in connection with the malaria. A number of cave forms were collected by I. Buresch and P. Beron. The materials of Konsuloff and Enderlein are related to their work on the black flies. Culicidal mosquitoes were collected by D. Bozhkov. In recent years, a significant number (over 10000 specimens) of studied at the moment families have been collected. A significant number of tropical forms (mostly alcohol preparations) were collected by P. Beron. A large number of dipterans have been collected lately by Malaise traps.