Abstract Objective: To identify Y chromosome material in an azoospermic male with an XX karyotype. Design: Case report. Setting: Faculty of medicine and Centro de Patologia Celular (CPC) medical center. Patient(s): A 33-year-old man with infertility. Intervention(s): G-banding, fluorescence in situ hybridization (FISH), polymerase chain reaction (PCR), and comparative genomic hybridization (CGH). Main Outcome Measure(s): FISH for X and Y chromosomes, PCR for the SRYgene and amelogenin gene in the Xp (AMGX) and (AMGY), and losses or gains with CGH. Result(s): FISH analysis using X and Y chromosome-specific probes showed an X chromosome containing Y chromosome sequences on the top of the short arm; this Y chromosome region was not visible by conventional cytogenetic analysis. PCR amplification of DNA showed the presence of the sex-determining region of the Y chromosome (SRY) and the amelogenin gene in the pseudoautosomal boundary of the X chromosome (AMGX). CGH confirmed the presence of the chromosome region Yp11.2-pter and detected the presence of the two otherwise normal X chromosomes. Conclusion(s): The two Xpter (XPAR1) pseudoautosomal regions present in this XX male suggest the need to reevaluate XX males using CGH and PCR to characterize the clinical variability in XX males due to genes other than those located on the Y chromosome.