Of 511 cases of brucellosis studied between December 1983 and February 1986, four (0.8%) had sternoclavicular (STCL) arthritis. Two were male and two female, and only one was younger than 50 years old. All four cases had significantly high specific IgG antibody titres (1 of 1280), measured by the indirect immunofluorescent (IIF) test, and two had Brucella melitensis isolated from their blood. In two cases, STCL arthritis was the presenting problem, and it was associated in one with ankle arthritis, hepatitis, renal impairment, orogenital ulcers and a haematological picture of myelodysplasia; in the other it was a relapsing STCL arthritis. In the remaining two cases, STCL arthritis was part of an extensive osteoarticular disease, which was associated in one with cachexia, liver cirrhosis, heart failure and prostatitis with urine retention, and in the other with severe thrombocytopenia. Excellent results were obtained from six to eight weeks' therapy with streptomycin, rifampicin and cotrimoxazole or tetracycline.