TB predisposes the patient to malnutrition and malnutrition increases the risk of developing active TB by 6 to 10 folds. Objectives: To study the socio demographic profile of the study population, to study the determinants of malnutrition among patients of Tuberculosis. Methods: A cross sectional study was conducted in the Government TB and Chest Hospital, Hyderabad from January to March 2023 (3 months). Ethical clearance was obtained from the institution ethics committee. The study population includes newly diagnosed active pulmonary TB patients aged more than 18 years, receiving TB treatment under DOTS and willing to participate in the study. Using the formula 4pq/l2, sample size of 110 was arrived. A pilot tested semi-structured questionnaire was used to collect data. Results: Most common age group was 38-47 years found in 54.5% of study subjects. Females constituted 64.5% of the study subjects. Subjects belonging to lower class were 44.55%, and 69% of the study subjects belonged to urban areas and 96.3% of the study subjects were married. Majority (86.3%) of the subjects never consumed alcohol, and (70.9%) were current smokers. Statistically significant relationship was found between younger age, female gender, rural residence, cigarette smoking, presence of diabetes and malnutrition. (p<0.05). Conclusion: Various determinants of nutritional status have emerged in our study. These include younger age groups, female gender, rural residence, cigarette smoking and presence of diabetes.