1. Since dietary factors are known to be related to nephrolithiasis, calcium stone-forming (CSF) patients were evaluated in terms of calcium, total protein of both animal and plant origin, carbohydrate and energy intakes, on the basis of 72-h dietary records during the week plus 24-h dietary records during the week-end. 2. The data for 77 calcium stone formers (57 with absorptive hypercalciuria and 20 with renal hypercalciuria) were compared to those for 29 age-matched healthy subjects. The body mass index of the CSF group was higher than that of healthy subjects (P < 0.05). Consumption of all nutrients was similar for both groups during the week but week-end dietary records for CSF showed higher calcium intake (586 +/- 38 vs 438 +/- 82 mg/day, P < 0.05), protein to body weight ratio (1.2 +/- 0.1 vs 1.0 +/- 0.5 g kg-1 day-1, P < 0.05) and animal protein (56 +/- 3 vs 40 +/- 3 g/day, P < 0.05) when compared with healthy subjects. 3. Comparison of hypercalciuria subtypes (renal hypercalciuria and absorptive hypercalciuria) did not indicate any difference in calcium or energy intake between groups, either during the week or during the week-end. However, the absorptive hypercalciuric group presented higher protein and animal protein consumption during the week-end. 4. These data suggest a low calcium intake in this population, even by stone formers. The higher animal protein consumption by our calcium stone formers observed during week-ends seems to be more important than calcium intake for stone formation.