200 rare species are included in the second edition of the Red Book of Penza Region. Information on the distribution of species in existing and planned protected areas should be clarified in the preparation of the next edition of the Red Book. Herbarium materials and literary information were used to clarify the information. 148 rare species of vascular plants (74% of them are listed in the Red Book of Penza region) are currently protected by the modern system of specially protected natural territories of Penza region. Populations of 13 of the 22 species listed in the Red Book of the Russian Federation are currently not known, two species are subject to exclusion due to incorrect identification. There are 86 protected species of vascular plants (43%) on the territory of the State Nature Reserve «Privolzhskaya lesostep». 114 species are protected (57%) only on the territory of natural monuments. 57 species do not have territorial protection in the region. Only 34 of them are known to have a population known to scientists. These species need priority protection measures. The existing system of protected areas needs significant optimization.