Osteochondritis dissecans of the shoulder joint was treated by arthroscopy in 126 dogs. Twenty-four dogs had bilateral surgery, making a total of 150 joints treated. The OCD flaps were removed in small pieces through the cannula or in a single piece through a stab incision. The lameness resolved completely within seven-60 days following arthroscopy in 137 out of 150 affected limbs. Within a subset of 47 dogs with unilateral OCD, it was found that lesions located on the caudo-medial region of the humeral head had a better functional outcome than those lesions located in the caudo-central region of the humeral head.