Background Cytogenetic and molecular studies of azoospermic and oligozoospermic males have suggested thepresence of azoospermia factors (AZF) in the Y chromosome.Deletion in AZF regions has been reported todisrupt spermatogenesis and cause infertility.Several candidate genes responsible for spermatogenesis have beenidentified in this region and some of them are thought to be functional in human spermatogenesis.And wereported clinical and molecular studies of Ychromosome microdeletions in Chinese.This study aimed atassessingthe frequency of microdeletions in Chinese men with idiopathic and nonidiopathic infertility problems anddicussing the clinical significance of the AZF region.Methods In this study, we screened 143 infertile men (62 with idiopathic infertilitas and 81 withnonidiopathic infertilitas), in whom karyotype, sperm count, hormonal parameters and fine needle aspirationcytology were evaluated.Genomic DNA was extracted from the peripheral leukocytes.Molecular analysis wasperformed by two multiplexpolymerase chain reactions (PCR) using a set of a sequence tagged sites (STS) from3 different regions of the Y chromosome: AZFa (sY84, sY86), AZFb (sY127, sY134), AZFc (sY254,sY255).Results Nineteen point four percent of idiopathic males (12/62, 19.4%) had microdeletions of either theAZFa, AZFb, AZFc or AZFb +c region.Significantly, a high frequency of microdeletions (9/81, 11.1%) wasfound in nonidiopathic patients with varicocele and cryptorchidism.No deletions were found in healthy fertilemen.There were no significant differences in the localization and extent of deletions between idiopathic andnonidiopathic patients.Conclusions The knowledge of the presence of these deletions in idiopathic and nonidiopathic cases isimportant to understand the prognosis, better management and counsel these patients accordingly.Furthermore,a more extended screening for Y chromosome microdeletions in idiopathic and nonidiopathic men, particularlycandidates for intracytoplasmic sperm injection, is recommended. Background Cytogenetic and molecular studies of azoospermic and oligozoospermic males have suggested the presence of azoospermia factors (AZF) in the Y chromosome. Detection in AZF regions has been reported todisrupt spermatogenesis and cause infertility. Selective candidate genes responsible for spermatogenesis have been identified in this region and some of them are thought to be functional in human spermatogenesis. And were wereported clinical and molecular studies of Ychromosome microdeletions in Chinese.This study aimed atassessingthe frequency of microdeletions in Chinese men with idiopathic and nonidiopathic infertility problems anddicussing the clinical significance of the AZF region. Methods In this study, we screened 143 infertile men (62 with idiopathic infertilitas and 81 with nonidiopathic infertilitas), in whom karyotype, sperm count, hormonal parameters and fine needle aspiration cytology were both. Genomic DNA was extracted from the peripheral leukocytes. Molecular analysis wasperfo rmed by two multiplexpolymerase chain reactions (PCR) using a set of a sequence from tagged sites (STS) from 3 different regions of the Y chromosome: AZFa (sY84, sY86), AZFb (sY127, sY134), AZFc (sY254, sY255) Nineteen point four percent of idiopathic males (12/62, 19.4%) had microdeletions of either the AZFa, AZFb, AZFc or AZFb + c region .ificantly, a high frequency of microdeletions (9/81, 11.1%) was found in nonidiopathic patients with varicocele and cryptorchidism. No deletions were found in healthy fertilemen. There were no significant differences in the localization and extent of deletions between idiopathic and nonidiopathic patients. Conclusions The knowledge of the presence of these deletions in idiopathic and nonidiopathic cases isimportant to understand the prognosis, better management and counsel these patients accordingly. Further eds, a more extended screening for Y chromosome microdeletions in idiopathic and nonidiopathic men, particularly candidates for intracytoplasmic sperm injection, is recommended