Summary Data from 10,769 dogs with rupture of the cranial cruciate ligament (ccl) were compared with data from a control population of 591,548 dogs to determine whether age, breed, gender, or body weight was associated with prevalence of ccl rupture. Prevalence of ccl rupture increased as dogs became older, with peak prevalence in dogs 7 to 10 years old. Among breeds represented by > 1,000 individuals, Rottweilers, Newfoundlands, and Staffordshire Terriers had the highest prevalence of ccl rupture, whereas Dachshunds, Basset Hounds, and Old English Sheepdogs had the lowest. Neutered dogs, whether male or female, had a higher prevalence of ccl rupture than did sexually intact dogs. The dog's age at the time of ovariohysterectomy was not associated with prevalence of ccl rupture. Dogs weighing > 22 kg had a higher prevalence of ccl rupture, compared with dogs weighing < 22 kg, and tended to rupture their ccl at a younger age.