Background: Pneumonia constitutes the primary cause of hospitalizations and is the foremost reason for admissions to intensive care units. In pediatric patients who are hospitalized due to severe pneumonia, electrolyte imbalance is a significant complication. The presence of hypokalemia at the same time as hyponatremia makes the clinical prognosis even more complicated in pneumonia cases. Both hyponatremia and hypokalemia have been linked to unfavorable outcomes in pneumonia cases. The monitoring of alterations in electrolyte levels is of paramount importance in order to avert complications that may result in heightened morbidity and mortality. It is imperative to investigate the alterations in electrolyte levels occurring in hospitalized pediatric patients diagnosed with severe pneumonia. Hypokalemia may occasionally be observed in pediatric patients suffering from severe pneumonia. The objective of this study was to assess the serum electrolyte levels, specifically sodium, potassium, calcium, chloride, and magnesium, in patients diagnosed with pneumonia. Method: This is a case control study that conducted on 150 children who were selected from those attending Bab El-sharia and Al Hussain university hospitals by sample random method from July 2023 to July 2024. Children were divided into 2 groups, aged more than 2 months and less than 15 years old and with moderate to severe pneumonia with no specified sex: Group 1 (n=100): patients with pneumonia. Group 2 (n=50): healthy controls (non-pneumonic cases). All the studied children were subjected to complete history taking, clinical examination with some labs. and radiological imaging. Results: Based on our findings, a statistically significant difference was observed in sodium levels between patients with pneumonia and control patients in general. In addition, the incidence of hyponatremia, particularly mild and moderate forms of the condition, was significantly different between the two groups. A statistically significant correlation has been established between serum sodium, potassium magnesium, calcium, chloride levels and the severity of pneumonia in patients, as indicated by a correlation coefficient of 0.292, which implies a mild correlation. A statistically significant correlation has been established between serum sodium levels and complications in patients diagnosed with pneumonia, as indicated by a correlation coefficient of 0.412, which implies a moderate degree of association. Conclusion: Hyponatremia is not uncommon finding in children with Pneumonia, hypocalcemia may be occurred also with pneumonia. The degree of hyponatremia seems to be related to the severity of pneumonia and days of hospital admission. On the other hand, potassium, chloride, and magnesium were not significantly different between the pneumonia and control groups.