The aim of this study was to evaluate systolic and diastolic cardiac functions in children treated with continuous ambulatory peritoneal dialysis (CAPD). This study included a total of 21 patients (12 boys, 9 girls), aged 23 months to 14 years (average age: 10.1 +/- 4.32 years). The mean duration on CAPD was 12.88 +/- 6.69 months (range: 2-22 months). Twenty age- and sex-matched healthy subjects served as controls. Evaluation was made at the beginning of CAPD treatment in these 21 patients. Tests were repeated in 9 of 21 patients who had completed a 1-year follow-up period. We measured systolic functions [ejection fraction (EF), and fractional shortening (FS)], and diastolic functions [early (E) and late (A) diastolic peak inflow velocities, and E/A ratio, as well as early diastolic flow deceleration velocity (EF slope) and time (dt) functions] using two-dimensional, M-mode, color Doppler echocardiography. Interventricular septum thickness was also recorded. Blood pressure (BP) levels were monitored serially in all patients. Statistical evaluation was made using Student's t-test. Compared with control subjects, systolic and diastolic parameters were significantly inversely affected in patients on CAPD (P < 0.05). The mean BP levels did not differ significantly between CAPD patients and controls. In 9 patients with a second measurement on CAPD, systolic and diastolic cardiac functions tended to have deteriorated. However, these changes were not statistically significant (P > 0.05). In conclusion, CAPD is the preferable option in children with end-stage renal disease to maintain stable cardiac functions. However, systolic and diastolic dysfunctions tend to progress in children on CAPD.