Microdeletions of the Y chromosome have been observed in some patients with cryptorchidism and severe defects of spermatogenesis. We investigated whether microdeletions of the Y chromosome may be present in patients with cryptorchidism and hypospadias. Peripheral blood was obtained from 20 male patients 5.8 +/- 4.1 years (range: 0.4-14 years) with cryptorchidism and hypospadias for somatic DNA analysis of Y chromosome using multiplex polymerase chain reaction. These patients had no identifiable genetic syndrome, other genitourinary malformations or an abnormal karyotype. We evaluated the presence or absence of amplification using a set of 34 different sequence-tagged sites (STS) in each patient. All patients showed normal length amplifications for each of the regions evaluated, suggesting that microdeletions of the Y chromosome are not a frequent cause of hypospadias associated with cryptorchidism.