RESUMEN
OBJECTIVE: This paper aimed to estimate the frequency of occurrence and the types of chromosomal abnormalities found in 141 infertile men with abnormal semen parameters. METHODS: the frequency and type of chromosomal abnormalities were determined with male mitotic karyotype analysis from peripheral blood through chromosome banding techniques before assisted reproduction procedures. RESULTS: In this series of 141 infertile men, 19 (13%) had chromosomal anomalies and 35 (25%) had polymorphic variants. The main chromosome abnormalities were reciprocal translocations and marker chromosomes in mosaic. CONCLUSIONS: These results stress the relevance of cytogenetic studies for infertile males as a diagnostic tool and a valuable input in genetic counseling.