Background: Lower respiratory tract infection(LRTI) is a single largest cause of death in children worldwide. Hyponatremia is the most common electrolyte disturbance in admitted patients of LRTI. This study may help in prognostication of disease in terms of course, complication and possible outcome in these patients. Objective: To estimate prevalence of hyponatremia in hospitalized patients of LRTI and to identify demographic, clinical and laboratory factors, complications and outcome associated with hyponatremia in patients with LRTI. Materials and Methods: Children between 1 month to 18 years with LRTI admitted in department of pediatrics in a tertiary care centre in central India, as per inclusion and exclusion criteria were enrolled and their detailed clinical history, physical examination, routine investigations and serum sodium levels, complication, treatment were recorded. Results: Out of 150 patients of LRTI admitted, hyponatremia was present in 43 cases (27%). Mild and moderate hyponatremia were present in 19.3% and 9.3% patients respectively. Hyponatremia was found to be more common in 1 to 5 years. Mean duration of hospital stay was longer in hyponatremic children. 69.8% of patients with hyponatremia on admission were found to have SIADH which was statistically significant. Mortality in patients with hyponatremia was 18.6%, which was significantly higher as compared to eunatremic patients where mortality was only 1.9%. Conclusion: Hyponatremia is a common association among hospitalized children with LRTI. Serum sodium level at the time of admission can be used for timely identification and intervention of at risk LRTI patients and may help in reduction of morbidity and mortality.