Jembrana is a disease similar to rinderpest, and found to affect Indonesian cattle and buffalo. Since the disease was first recorded in 1964 much has been learnt about the lentivirus determined as the causative agent. These proceedings arise from a workshop funded by ACIAR held in Bali, Indonesia in June 1996 to review the knowledge of the virus, its epidemiology and prospects for controlling the disease. Other lentivirus diseases of cattle and sheep are also discussed.