Heart and kidney dysfunction often coexist, and increasing evidence supports the interaction of these two organs, as demonstrated by the clinical condition known as cardiorenal syndrome (CRS). We report a pediatric patient with end-stage renal disease (ESRD) who developed a dilated cardiomyopathy and decompensated heart failure after undergoing unilateral nephrectomy and while on maintenance peritoneal dialysis. He showed marked improvement in his cardiac function with the addition of intensive hemodialysis. We discuss the pathophysiology of cardiorenal syndrome in patients with ESRD and suggest that intensive dialysis may be an effective therapy for this condition.