Forty four adult patients, 34 males and 10 females, with urinary stones were seen over a six-month-period at Muhimbili Medical Centre, Dar es Salaam. Most patients were peasants and semiskilled workers. 8 of the patients were Arabs, which suggests a high predisposition for this race. 12 of the patients had a history of having suffered from bilharzia. There was a high proportion of bladder (and urethral) stones (30%) but upper urinary tract stones were still predominant (70%). Of 20 patients whose stones were available for analysis, 8 were composed of calcium oxalate, 7 of calcium phosphate and 5 of mixed composition. The ratio of stone patients to all hospital admissions of 243 per 100,000 suggests the prevalence of urinary stone disease is comparable to that found in Western countries.