Anaesthetic complications have been studied intermittently in small animal practice. Current estimates suggest that approximately 0.1-0.2% of healthy and 0.5-2% of sick dogs and cats die of an anaesthetic-related death. This is substantially greater than the risk of mortality reported in human anaesthesia. Recent work has identified the post-operative period as the highest risk period and has documented a number of risk factors for mortality. Knowledge of factors associated with anaesthetic-related death and high risk peri-operative periods could aid patient management and reduce complications.