The lamprey collections of the National Museum of Natural History – Sofia and the Regional History Museum – Ruse were examined in order to determine the species composition of the family Petromyzontidae in Bulgaria. In contrast to the four species of lampreys reported in the scientific literature as being present in Bulgaria, i.e. Lampetra fluviatilis, L. planeri, Eudontomyzon danfordi, and E. mariae, only the latter species was determined in the Bulgarian material. The distribution of this species in Bulgaria is restricted to the Danube River basin. The occurrence of E. hellenicus in the Bulgarian segment of the Struma River basin is anticipated in all probability. The species composition of lampreys inhabiting the streams emptying directly into the Black Sea remains to be investigated.