Objective: The present study was undertaken to synthesize a human Y chromosome specific probe and to confirm the usefulness of the probe for fluorescence in situ hybridization (FISH) in various types of human cells. Methods: An approximately 400 bp DNA fragment of the DYZ1 sequences was synthesized by PCR using digoxigenin labeled dUTP (dig-PCR). The fidelity of probe was tested by FISH for cultured and uncultured human lymphocytes, amniocytes, chorionic villus cells, embryos, sperms, and germ cells of seminiferous tubule. Results: The human Y chromosome specific probe hybridized specifically to Y chromosome of the cells that had been tested. This probe assigned to the Yq12 region where the DYZ1 repetitive sequence is concentrated. Conclusion: We have identified a human Y chromosome specific probe that hybridized specifically to the Y chromosome by FISH for various types of uncultured as well as cultured cells. Therefore FISH technique using human Y chromosome specific probe should be useful for clinical application as a diagnostic tool for the detection of human Y chromosome.