The VetCompass Programme uses clinical information on 2 million dogs shared from over 450 UK veterinary practices to examine health and welfare issues. A current hot topic in canine health asks whether crossbred dogs are healthier than purebred dogs and which breeds are the healthiest. Although these might appear to be simple questions, VetCompass studies show that answers are not quite so easy. Comparing crossbred and purebred dogs, VetCompass studies show, on the one hand, that crossbreds live 1.2 years longer than purebreds (O'Neill et al 2013) but, on the other hand, crossbred dogs have lower occurrences for only three from the top 20 disorders recorded in dogs (O'Neill et al 2014). So the answers are not that clear; crossbred dogs do appear to benefit from a hybrid vigour effect for general characteristics such as longevity but seem to enjoy less advantage when it comes to the occurrence of specific common disorders. On the question of the healthiest breeds, the lifespan of breeds varies widely, from 5.5 years in the Dogue de Bordeaux up to 14.2 years in the Miniature Poodle (O'Neill et al 2013). However, across many common and important disorders, breeds at high risk for one disorder are often at lower risk for another disorder (Kearsley-Fleet et al 2013, Mattin et al 2014, O'Neill et al 2014, Mattin et al 2015, Summers et al 2015). We have come a long way in the past few years and we now know which breeds live the longest and which breeds are most at risk for specific disorders However, we do not yet have an answer for which breeds are the healthiest overall. VetCompass work will continue to help answer these vexing questions.