In the urine of a patient with chronic prostatitis, renal microlithiasis and acute cystitis we found the ciliate protozoa Colpoda spp., both in vegetative and cystic form. The entry point was most likely the urinary tract. Keeping in mind that only four more cases of Colpoda spp. existent in human urine have already been described, and that in the case of our patient the ciliate was present at repeated examinations of his urine, we presumed that it is not only a spurious infection of the urogenital tract. It still remains to be analyzed whether this ciliate belongs to a species of Colpoda adapted to parasitism in homeothermae and whether it can be pathogenic for humans.