Serum electrolyte  abnormalities are quite common in children who need intensive care.  They have a significant contribution to morbidity and mortality.  Electrolyte imbalance occurs frequently and should be looked for in all severely  ill patients. Hyponatremia is of euvolemic type in almost all acute infection except in Diarrhea which can go undiagnosed clinically, presence of hyponatremia significantly  increase the morbidity and mortality.   Early detection and institution of rational therapy for hyponatremia should be done  regardless of underlying disease. Careful correction of sodium level is warrented to avoid fatal neurological sequalae.        In the presence of mixed electrolyte abnormalities, the  risk is even higher. In general, CNS  diseases, respiratory diseases and infectious diseases are more commonly associated with  serum electrolyte abnormalities.  SIADH quite commonly occurs in euvolemic hyponatremia,  in respiratory and CVS disorders.  There are no reliable clinical predictors of electrolyte abnormalities except in cases of  hyponatremia and hypokalemia; and the signs of electrolyte imbalances often merge with  those of the underlying diseases. In addition, electrolyte abnormalities  occur commonly in an  ICU setting.  In view of  these  facts, a routine estimation of serum electrolytes should be  considered in all patients getting admitted to PICU. Thus this study brings out the salient aspects of sodium and potassium abnormalities in severely ill, and  focuses on the importance  and need to recognize the  abnormalities  and acts as good predictor of  morbidity and mortality in PICU.