To observe the relationship between microdeletions of AZF( azoospermia factor) on Y chromosome in male with idiopathic azoospermia and severe oligozoospermia.Only patients with an apparently normal 46,XY karyotype and normal FSH, LH and T were included in this study. Multiplex PCR was used to detect the sequence-tagged sites( STS) as follows :sY84, sY86, sY127, sY134, sY152, sY153, sY254, sY255, and ZFX/Y was used as internal control gene.No microdeletion was detected in the control whereas 8 microdeletion cases existed in 67 idiopathic azoospermia and severe oligozoospermia, including 4 in AZFc, 2 in AZFa + AZFc, 1 in AZFc + AZFb, and 1 in AZFb. The prevalence rate of microdeletion was 11.94%, which was statistically different from the control.Microdeletions in the AZF regions on the long arm of the Y-chromosome are associated with idiopathic azoospermic and severely oligozoospermic men. Multiplex PCR was a rapid and reliable method for screening microdeletions of AZF.