INTRODUCTION: CYTOGENETIC ABNORMALITIES AND GENE ALTERATIONS IN THE FORM OF AZF MICRODELETION CONTRIBUTE GREATLY TO MALE INFERTILITY. IN THIS STUDY, WE DETERMINED GENETIC COMPONENT IN THE ETIOLOGY OF IRANIAN INFERTILE MEN.MATERIAL & METHODS: 86 INFERTILE MEN WERE KARYOTYPE WITH STANDARD G-BANDING AND SCREENED FOR AZF MICRODELETIONS BY PCR.RESULTS: CYTOGENETIC STUDY REVEALED CHROMOSOMAL ABNORMALITY IN 11 SUBJECTS (12.79%) AND 7 SUBJECTS (8.13%) WERE DETECTED TO HAVE Y CHROMOSOME MICRODELETIONS. THE CHROMOSOMAL ABNORMALITIES OBSERVED WERE: 46, XY (T15; Y), 46, XY, DEL (Y) (Q12), MOS45, X/46, XY, 46, XY, -10, +DER (1P10), T (1; 10) (Q10; P15:: Q26), 46, XY (T13; 21), 47, XXY. THE AZF MICRODELETIONS WERE OBSERVED EITHER SOLELY IN AZFC (4 OUT OF 7 EQUAL TO 57.14%) OR IN BOTH AZFB AND AZFC LOCI CONCURRENTLY (3 OUT OF 7 TO EQUAL 42.85%). IN FOUR INDIVIDUALS BOTH CHROMOSOMAL ABNORMALITY AND AZF MICRODELETION WERE DETECTED. THEREFORE, IN TOTAL 14 CASES (16.27%) SHOWED GENETIC ABNORMALITY….