The diets of 51 men with renal stones were compared with those of 94 age-matched controls, using a measured record of all food and drink consumed during 4 days. The mean intakes of three nutrients suspected in the aetiology of renal stones, animal protein, refined carbohydrate (sugar) and dietary fibre, were similar for both cases and controls. However, the cases had a higher intake of ascorbic acid. A greater proportion of cases had low fluid intakes or took no exercise in their leisure time.