In this case report, the occurrence of medial coronoid disease (MCD) is described in an elevenyear-old Labrador retriever. A left frontleg lameness had started six months before presentation.Radiographs showed minimal pathology and computed tomography (CT) demonstrated a discretefissure of the medial coronoid process. Arthroscopy confirmed the presence of a coronoidlesion, visible as chondromalacia. Treatment was performed by arthroscopic removal of the diseasedcartilage and subchondral bone. Despite the successful procedure, the dog needed continuousphysiotherapy to maintain an acceptable gait.MCD is a developmental disorder mainly affecting young large breed dogs. However, thedescribed dog was already eleven years old. Nevertheless, the duration of lameness was rathershort and the imaging and arthroscopic findings could not demonstrate a chronic problem. In theliterature, little information is available about the etiology, prevalence and treatment outcome ofmedial coronoid pathology in old dogs.