Several factors conspire to make the definition of ‘sudden death’ in sheep problematic. The most commonly accepted definition is death that occurs since the last inspection (ie, within 12 to 24 hours). However, it can be challenging for the shepherd to detect early clinical signs of disease in sheep due to extensive husbandry, limited supplementary feeding and sometimes, despite the legal requirements, infrequent inspection. In addition, group sizes tend to be large, making recognition of individual animals difficult. Consequently, veterinary investigation into any case where sheep have been found dead may not always reveal an acute cause. This article aims to consider such situations as well as those of truly ‘sudden death’.