Background: Non‑adherence to anti‑tuberculosis (TB) treatment adversely affects treatment success rate. It increases disease morbidity and mortality. Also, it contributes significantly to the development of drug resistance. Aim: To identify risk factors for non‑adherence to anti‑TB treatment by new pulmonary TB patients. Subjects and Methods: It is a prospective cohort study at 21 TB treatment centres in E ward of Mumbai Municipal Corporation. All sputum smear positive new pulmonary TB patients initiated on treatment regimen of short course chemotherapy fro 1st January to 30th June of a calendar year were enrolled and followed up till any final outcome as per revised national TB control program. Non‑adherence was defined as interruption of anti‑TB treatment for ≥ 1 month. The factors were identified by univariate and logistic regression analysis. Results: We studied 156 newly diagnosed pulmonary TB patients. Out of these 78 (50%) were non‑adherent to anti‑tuberculosis treatment (ATT). Independent risk factors for non‑adherence were identified as male gender (P = 0.035) and lack of knowledge of importance of regular treatment (P = 0.001). Being female sex worker (FSW) was also an absolute risk factor for non‑adherence. Conclusions: There is immense need for continuous, effective and reinforcing health education to the patient and his family. Special groups like males in the age group of 15‑49 years, patients who do not have any family support like migrants, FSW need special attention to ensure adherence to ATT.