A patient with severe hyponatreamia secondary to chronic renal failure was treated with peritoneal dialysis (PD). On the third day of admission, she developed progressive obtundation. Neurological examination showed bilateral brisk reflexes with intact brain stem reflexes. Magnetic resonance imaging demonstrated patchy demyelination of the pontine area indicating central pontine myelinolysis (CPM). Despite supportive measures, the patient died on the fifteenth day of admission. The rate of correction of hyponatraemia with peritoneal dialysis can be rapid and detrimental to hyponatraemic chronic renal failure patients and careful monitoring of serum sodium level is advocated.