Mast cell tumours are the most common cutaneous neoplasia in dogs and can present in a variety of manners, demonstrating a wide range of biologic behaviour; each case, therefore, needs to be approached individually. This lecture will cover the important aspects of diagnosing and staging patients with mast cell tumours in order to plan the optimum treatment approach. There are a multitude of treatment options, both medical and surgical, depending on individual patient and tumour factors and the latest treatment advances will be discussed. This lecture aims to help guide your decision making when next faced with a mast cell tumour in practice; after the lecture you should be able to understand the diagnostic approaches to mast cell tumours and the importance of staging, be able to individualise your treatment approach depending on clinical presentation and laboratory data, and know the latest treatment options for mast cell tumours.