Metabolic acidosis is observed in the pediatric intensive care unit (PICU) in several conditions including sepsis, intoxications, and severe catabolic states. It is occasionally seen due to acute decompensation in an inborn error of metabolism (IEM). Persistent acidosis results in a decrease in myocardial contractility, cardiac output, and catecholamine responsiveness. The mainstay of treatment of metabolic acidosis has been intravenous sodium bicarbonate infusion. However, the large amounts of sodium bicarbonate sometimes required can be hazardous resulting in hypernatremia, hypervolemia, and hyperosmolality. We report a 3-year child who presented with persistent lactic acidosis due to an IEM whom we treated with peritoneal dialysis (PD) using a bicarbonate-buffered dialysate. The child recovered uneventfully within 72 hours of dialysis. Peritoneal dialysis using a bicarbonate-buffered dialysate is a safe and simple method of treating persistent severe acidosis in the PICU. How to cite this article: Kalbhande A, Gajare U, Shanbag P. Peritoneal Dialysis Using a Bicarbonate-buffered Dialysate in a Child with an Inborn Error of Metabolism Presenting with Severe Acidosis. Indian J Crit Care Med 2020;24(3):200-202.