Babesia microti and B. divergens, the etiological agents of human babesiosis, are transmitted by the bite of Ixodes ricinus. The purpose of this study was differentiation of those two species in ticks collected in urban woods in the city Szczecin (north-western Poland). The prevalence of the DNA of Babesia were investigated by PCR amplification with primers to the fragment from a gene encoding the nuclear small-subunit ribosomal RNA (SS-rDNA). We examined a total of 533 specimens of Ixodes ricinus. The mean infection rate was 16.3%. Our results indicate that a B. microti and B. divergens--specific PCR test may provide a sensitive tool also for the laboratory diagnosis of human babesiosis.