Maintenance dialysis usually serves as an interim treatment for children with end-stage renal disease (ESRD) until transplantation can take place. Some children, however, may require dialytic support for an extended period of time. Although dialysis improves some of the problems associated with growth failure in ESRD (acidosis, uremia, calcium, and phosphorus imbalance), many children continue to grow poorly. Therefore, three different dialysis modalities, continuous ambulatory peritoneal dialysis (CAPD), cycler/intermittent peritoneal dialysis (CPD), and hemodialysis (HD), were evaluated with regard to their effects on the growth of children initiating dialysis and remaining on that modality for 6-12 months. Growth was best for children undergoing CAPD when compared with the other two modalities with regard to the following growth parameters: incremental height standard deviation score for chronological age [-0.55 +/- 2.06 vs. -1.69 +/- 1.22 for CPD (P < 0.05) and -1.80 +/- 1.13 for HD (P < 0.05)]; incremental height standard deviation score for bone age [-1.68 +/- 1.71 vs. -2.45 +/- 1.43 for CPD (P = NS) and -2.03 +/- 1.28 for HD (P = NS)]; change in height standard deviation score during the dialysis period [0.00 +/- 0.67 vs. -0.15 +/- .29 for CPD (P = NS) and -0.23 +/- .23 for HD (P = NS)]. The reasons why growth appears to be best in children receiving CAPD may be related to its metabolic benefits: lower levels of uremia, as reflected by the blood urea nitrogen [50 +/- 12 vs. 69 +/- 16 mg/dl for CPD (P < 0.5) and 89 +/- 17 for HD (P < 0.05)], improved metabolic acidosis, as indicated by a higher serum bicarbonate concentration [24 +/- 2 mEq/l vs. 22 +/- 2 for CPD (P < 0.05) and 21 +/- 2 for HD (P < 0.05)]. In addition, children undergoing CAPD receive significant supplemental calories from the glucose absorbed during dialysis. CAPD, and possibly, other types of prolonged-dwell daily peritoneal dialysis appear to be most beneficial for growth, which may be of particular importance for the smaller child undergoing dialysis while awaiting transplantation.