Foraminifera of the Lower and Middle Portlandian and Ostracods of the Purbeckian facies of the Upper Portlandian of Polish Lowlands were studied; 63 foraminiferal species (including 12 new) and 21 ostracod species (including one new, Cypridea praealta sp.n.) are described. Analysis of stratigraphic ranges of the microfauna made it possible to distinguish 5 foraminiferal zones (I-V) of the Lower and Middle Portlandian and 5 ostracod zones (F-B) of the Purbeckian facies of the Upper Portlandian. The foraminiferal microfauna of the Portlandian of Poland appears most similar to those from the Lower and Middle Volgian of the Russian Platform.