Introduction: Hyponatraemia is reported to be the most frequently occurring electrolyte imbalance which is most commonly seen in critically ill children. The aim and objective of this study was to find out the frequency of hyponatremia in pneumonia and to find the association and significance of hyponatremia in patients affected with Pneumonia. Materials and Methodology: This study has been designed as an in-patient hospital based prospective study will be conducted to evaluate the association and significance of hyponatremia in Paediatric patients affected Pneumonia being treated in RIMS, Raichur. 120 patients will be selected as the study participants for the study after obtaining informed consent from the parents as well. Statistical analysis should be carried out by using appropriate statistical tests. Both the groups have to be compared by the student t – test for continuous variables and Chi-square/ Fischer’s exact test for all the categorical variables. The p value of less than 0.05 will be taken as significant. The data will be analysed by statistical software SPSS latest version. Results: . The patient’s serum sodium level ranged from 124 - 145 mEq/L (both found at 0 hour) and none were observed to have hypernatraemia.