Cryptorchidism is one of the most common developmental defects in purebred dogs. Single gene markers (called SNPs) are being used to investigate the associations in Siberian huskies between candidate genes (INSL3, LGR8, ESR1, HOXA10, MIS, CGRP and other positional candidates) and cryptorchidism. Findings of causative mutations in candidate genes will be useful in dog breeding programs to reduce the incidence of cryptorchidism.