Paratuberculosis was studied for three years in a large goat herd. Post mortem lesions were seen mainly in the ileum and mesenteric lymph nodes where caseation was often present. In three successive years the annual faecal excretor rate was 15, 9 and 13 per cent despite removal of positives. Faecal culture and an agar gel immunodiffusion test proved useful for detecting the disease in live goats, but complement fixation and tuberculin tests were of less value. The prospects of controlling the disease are discussed.