The cytogenic study of a male sent to the Genetics Unit due to sterility and azoospermia revealed a translocation between chromosomes 1 and 15. The patient's age of 34, at the time of the study, and his normal phenotype. The karyotype revealed a balanced t translocation (1;15) with rupture points at 1 q21 and 15 p13, the denomination of which would be: 46,XY, t(1;15) (q21;p13). Chromosomic analysis of the other members of the family confirmed a de novo translocation.