Summary Ninety-seven adult Zebu cattle with hygromas, 32 with arthritis and two showing long calving intervals were investigated for brucellosis. 92 per cent of hygromatous cattle, 62 per cent of arthritic cattle and both animals having long calving intervals were serologically positive and 65 per cent of milk samples were positive by the Milk Ring Test. Hygromas were found on the jaw, bursa, thigh, flank, hip, shoulder, neck and joints. Hygroma aspirates gave higher titres than sera in the serum agglutination test. IgG 1, IgG 2, and IgA were detected in all the aspirates and all but one contained IgM. Cattle with hygromas are a potential source of infection to other animals and a serious public health problem.