A pedigree study of 536 registered Dachshunds with intervertebral disk disease revealed patterns of occurrence consistent with a genetic model involving the cumulative effect of several genes, with no dominance or sex linkage, subject to environmental modification. In 2 families studied, there were 52 cases of IDD among 84 Dachshunds in 15 litters, a prevalence of 62%, as compared with the estimated breed prevalence of 19%. It was concluded that Dachshunds from high-prevalence lineages should be considered to be genetically high risk and that breeders should avoid using them in breeding.