Hypokalemia occurs frequently in patients undergoing peritoneal dialysis (PD). However, the therapeutic strategy may differ from that of non-PD-related hypokalemia. We investigated clinical features and related factors of de novo hypokalemia in incident PD patients. We retrospectively enrolled 82 normokalemic patients starting PD at Gachon University Gil Hospital, Korea. The patients were divided into hypokalemia (K+<3.5 mEq/L) and normokalemia (3.5 mEq/L< or =K+<5.5 mEq/L) groups based on the plasma potassium levels at month 13, and then clinical parameters including peritoneal function and adequacy tests and biochemical parameters were compared. Eight patients who showed hyperkalemia (K+> or =5.5 mEq/L) at month 13 were excluded from our analyses. The incidence of hypokalemia in PD patients was 7.3% in a year. The de novo hypokalemia (n=6) and normokalemia (n=68) groups had no significant differences in baseline characteristics. The serum albumin levels and normalized protein equivalent of nitrogen appearance (nPNA) at month 1 were not significantly different between the two groups. At month 13, on the other hand, serum albumin levels and nPNA were significantly lower in the hypokalemia group (P=0.014; P=0.006, respectively). Kt/Vurea, residual renal function, dialysate-peritoneal creatinine ratio, and glucose load were not significantly different between the two groups. Hypokalemia occurring after initiation of PD may largely be associated with poor nutritional status.