Cranial cruciate ligament (CCL) deficiency is the leading cause of lameness of the canine stifle and has important consequences in terms of morbidity and cost associated with its management. In spite of this impact, development of preventive strategies remains in its infancy, largely because of gaps in our understanding of the complex and likely multifactorial origin of CCL deficiency. The purpose of this article is to provide a critical review of the literature related to the pathogenesis of CCL deficiency and place this evidence in the context of potential preventive measures. Trauma accounts for a minority of CCL ruptures in dogs, whereas progressive degeneration of the ligament has been attributed to a variety of factors that may be broadly classified as genetic, conformational, environmental, immune-mediated, and inflammatory. Genetic screening appears promising as a long-term option in selected breeds while immunomodulating therapies may be implemented in the nearer future to reduce the incidence of contralateral disease in dogs with unilateral CCL deficiency. Preventive modification of conformation factors may be applicable to most breeds predisposed to CCL deficiency but requires further investigations into the relative contribution of individual factors, as well as into the feasibility, and potential risks of large-scale implementation.