The applicability of real-time PCR amplification of the chromosome Y marker DYS14 for sex determination was studied. With this aim, real-time PCR of DYS14 (located within the TSPY1-encoding gene) was performed in plasma DNA specimens obtained from 30 men and 30 women. The PCR results showed that 30 specimens were of male and the other 30 were of female origin. All the results were confirmed by the tests for the SRY marker conventionally used in forensic examination. The detection limit for the DYS14-containing DNA region was established in dilution experiments and was equal to 6.7 pg of DNA (two copies of the genome), which corresponds to 6.7 ng of DNA (2000 copies of the genome) in 1 ml of blood. This level of sensitivity allows sex determination in specimens with small amounts of genetic material. The method can be used for noninvasive prenatal diagnostics of sex-linked congenital diseases and in forensic medical examination.