Анотация: Trichomoniasis is a sexually transmitted disease of cattle caused by Tritrichomonas foetus. Other species of trichomonads have been recently isolated from the prepuce of virgin bulls. It is not clear whether these non-T. foetus isolates are also present on the prepuce of breeding bulls. The traditional diagnostic test for T. foetus involves collection of preputial or vaginal samples followed by culturing and microscopic examination. Recently, polymerase chain reaction (PCR) techniques have been described for use as diagnostic assays. The objective of this study was to use a PCR assay for detecting T. foetus in bull`s semen samples. In a PCR assay, six out of 45 (13.3 percentage) semen samples showed a 372 bp amplicon following PCR with primers TFR 1-2 but no amplicon when primers TFR 3-4 were used. The observed amplicons were related to non-T. foetus organisms. Our study demonstrated that the PCR assay was an effective method for differentiation of T. foetus from other trichmonad species