The recent stratigraphical and paleontological research in the Jurassic/Cretaceous boundary sequence in central Poland confirmed a validity of the hitherto accepted local ostracod zonation. Six ostracod zones have been compared with the zones distinguished in England, France and Germany. From 51 ostracod species and subspecies recorded in the sequence of superposing marine-brackish and brackish-fresh-water sediments the author describes the following new species and subspecies: Limnocythere biverrucosa, Timiriasevia polonica, Cypridea aleksandrowiensis, C. wandae, C. binodosa polonica, C. dunkeri spinosa, C. granulosa polonica, C. lata polonica, C. obliqua polonica, C. prealta iuvencula and C. tumescens granulosa.