Background& Objective: Microdeletions of the Y-chromosome removing the azoospermia factor (AZF) region are the most frequent molecular genetic cause of spermatogenic failure. Although there is still no definitive consensus on the relationship between the type of microdeletion and the resulting sperm defect, microdeletions in AZFa lead mostly to Sertoli cell only syndrome, mutations in AZFb provoke interruption in meiosis I and mutations in AZFc result in hypospermatogenesis. Our objective is to evaluate the frequency and types of Y-chromosome microdeletions in patients with idiopathic nonobstructive azoospermia (NOA) and its relationship with successful sperm retrieval.