We have studied peripheral blood samples for chromosomal anomalies in 110 consecutive patients who had cryptorchidism and/or hypospadias. Of the patients 7 (6.4%) were found to have chromosomal anomalies. The incidence of chromosomal anomalies in patients with cryptorchidism only was 4/83 (4.8%), in patients with hypospadias only the incidence was 1/18 (5.6%) and in concomitant cases the incidence was 2/9 (22.2%). Of 69 patients with cryptorchidism and/or hypospadias who did not have any other congential abnormalities, 3 patients (4.3%) were found to have sex chromosomal anomalies. However, of 41 patients associated with generalized congenital abnormalities including mental and growth retardation, we found 4 patients (9.8%) with autosomal anomalies. We conclude that most children with multiple associated abnormalities other than cryptorchidism and/or hypospadias should have chromosome analysis. Moreover, attention should be paid to sex chromosomal anomalies, even when patients with cryptorchidism and/or hypospadias do not have any associated generalized physical anormalities.