Background: Hyponatremia is one of the most common electrolyte disturbances seen in hospitalized pulmonary tuberculosis (PTB) patients and may reflect disease severity. Indian data are limited, particularly from high-burden states such as Rajasthan. Objectives: To determine the prevalence and severity of hyponatremia in newly diagnosed sputum smear–positive pulmonary tuberculosis patients and to describe their demographic and clinical profile. Methods: This descriptive cross-sectional study was conducted in the Department of Respiratory Medicine, Institute of Respiratory Diseases, tertiary care hospital in Rajasthan. A total of 140 newly diagnosed sputum smear–positive PTB patients were included over one year. Serum sodium levels were measured at diagnosis and categorized as mild (130–134 mmol/L), moderate (125–129 mmol/L), and severe (<125 mmol/L). Sociodemographic and clinical parameters were recorded and analyzed. Results: The prevalence of hyponatremia (<135 mmol/L) was 45%. Severe hyponatremia was seen in 10%, moderate in 14%, and mild in 21% of patients. Most participants were aged 41–60 years (53.6%), male (80.7%), and from rural areas (90%). A statistically significant association was observed between serum sodium and age group (p = 0.00001), gender (p = 3.35×10⁻⁵), BMI (p = 6.22×10⁻⁴), occupation (p = 2.36×10⁻⁴), chest X-ray findings (p = 6.12×10⁻⁴), and sputum AFB grading (p = 0.02). Conclusion: Hyponatremia is highly prevalent in PTB patients, particularly among females, underweight individuals, and those with advanced radiological and bacteriological disease. Routine sodium monitoring is recommended for early detection and management.