We studied the hemodynamic responses of peritoneal dialysis (PD) in three children following open heart surgery. Hemodynamic measurements were made prior to a dialysis run, following the instillation of dialysis solution (20 ml/kg), and immediately prior to and 5 min after drainage of the peritoneal cavity. The same protocol was repeated 48 h later. There was a significant increase in right atrial pressure (RAP) and mean pulmonary artery pressure upon instillation of the dialysate into the peritoneal cavity (p less than 0.01). However, cardiac index, mean arterial blood pressure (MAP), systemic (SVRI) and pulmonary vascular resistances (PVRI), left atrial pressure (LAP), and oxygen saturation did not change significantly. There were no significant differences between responses in the initial study and that performed 48 h later. PD is associated with modest right-sided hemodynamic changes which, in this small group of patients, did not compromise patient care.