Two species of the fenestrate genus Fenestrapora Hall, 1885 are described from the Middle Devonian (middle Eifelian-lower Givetian) of the Rhenish Massif, Germany. The species Fenestrapora transcaucasica Morozova and Lavrentjeva, 1998 is known from the Middle Devonian (Eifelian) of Transcaucasia, Azerbaijan, and from the Middle Devonian (Eifelian) of Sauerland, Germany. One species is new: Fenestrapora tuberculata sp. nov. Numerical statistics were tested for species discrimination of the studied material of three Fenestrapora species from the Lower Devonian of Spain and Middle Devonian of Germany. Discrepancies in the taxonomical and numerical assignment of the studied samples are explained by restriction of the involved characters and their affection by environmental conditions.