Ultrasonography is a cost-effective, non-invasive technique, which can be performed in conscious dogs. It frequently contributes valuable and even crucial diagnostic information in patients with lameness attributed to the stifle joint. Within the first part of this article, technical requirements and limitations as well as the standardized scanning protocol and ultrasonographic anatomy of the stifle joint are described. Additionally, ultrasonographic features of common pathologies of the stifle joint, including cranial cruciate ligament rupture and meniscal pathologies, are discussed. The second part of the article focuses on the ultrasonographic approach to other, less common pathologies of the canine stifle joint, including impaired wound healing and congenital, neoplastic, developmental and traumatic disorders.