Renal osteodystrophy (ROD) is one of the mostfrequent complications in pediatric uremic patients on peritoneal dialysis (PD), and each case requires a different therapeutic approach. In the present study, we characterized ROD in pediatric patients on chronic PD. We studied 20 patients (12 boys, 8 girls) for a 12-month period. The mean age of the patients was 5.82 +/- 5 years. We allocated each patient to one of three groups according to intact parathormone (iPTH) value: group 1, iPTH < or = 150 pg/mL, n = 12; group 2, iPTH 151 - 400 pg/mL, n = 2; and group 3, iPTH > or = 401 pg/mL, n = 6. Monthly, we recorded plasma calcium, phosphorus, and alkaline phosphatase; Kt/V; normalized protein equivalent of total nitrogen appearance (nPNA); and calcitriol dose. Growth was registered as the Z height/age. Student t-test and analysis of variance for repeated measures were used for the statistical analyses. A value of p < 0.05 was considered significant. All 20 patients completed 6 months of follow-up; 9 patients completed 12 months. At months 1, 6, and 12, vitamin D doses for groups 1 and 3 were significantly different (p < 0.05), as expected. Mean values of iPTH for groups 1 and 3 were 52 +/- 47 pg/mL and 1239 +/- 718 pg/mL respectively, p < 0.05. At 6 months' follow-up, iPTH values had changed to 163 +/- 177 pg/mL for group 1 and 544 +/- 249 pg/mL for group 3 (p < 0.05), butfor group 3 that trend was lost at 12 months' follow-up, when their mean iPTH value rose to 972 +/- 420 pg/mL. Patients who had been started on PD less than 6 months before entering the study (60% of patients) showed a mean iPTH value of 629.13 pg/mL. Patients with more than 6 months on dialysis before entering the study showed an iPTH value of 115.53 pg/mL (p < 0.05). At 6 months' follow-up, iPTH values in groups 1 and 3 both showed a change toward the value range for group 2. At month 12, iPTH values in group 1 continued to show the same tendency, but iPTH values in group 3 showed a tendency to return to their initial levels. Low-turnover ROD was highly prevalent in the study, correlating strongly with time on dialysis.