In many social vertebrates, variation in group persistence exerts an important effect on individual fitness and population demography. However, few studies have been able to investigate the failure of groups or the causes of the variation in their longevity. We use data from a long-term study of cooperatively breeding meerkats, Suricata suricatta, to investigate the different causes of group failure and the factors that drive these processes. Many newly formed groups failed within a year of formation and smaller groups were more likely to fail due to collapse. Groups that breed successfully and increase their size, could persist for several years, even decades. For long lived groups, the principal cause of failure for was infection with tuberculosis, Mycobacterium suricattae, a fatal disease that commonly spread throughout the group and killing group members. Infection risk was higher in groups with mobile individuals, that were small or experienced immigration.