Background:This study assessed level of non-adherence to anti tuberculosis (TB) therapy among pulmonary TB patients, compares various factors among adherent and non-adherent TB patients, stressing on reasons for non-adherence at a tertiary care hospital. Methods: This institution based observational and cross-sectional study was conducted interviewing patients with pulmonary TB and assessed using Moriskys medication adherence scale-8 (MMAS-8), a pre-tested structured questionnaire based scoring system of patients treated for pulmonary TB at district TB centre SIMS, Shimoga. Descriptive statistics were employed. Results: Among 70 cases analysed, 57 were males and 13 females, with mean age group of 41.32±8.63 and mean MMAS score of 2.23±1.87. 53.33% patients were on continuous phase of treatment. The level of non-adherence were as follows, high= 18%, medium= 38% and low= 44%. The common cause for nonadherence was forgetfulness (66%) reasons being: betterment of symptoms (54%), sickness after taking medication (31%), distance of travel: far (15%). Many were labourers (62%), with low literacy rate, also chronic alcoholics (72%) and smokers (73%). Female with moderate literacy and not addicted to alcohol/smoking showed high adherence compared to males (p<0.05%). Conclusions:As prevalence of non-adherence is high, especially Patients on continuous phase of TB treatment, there arises immense need for continuous and effective health education to patients' and their family regarding the adverse effects and the need for high level of adherence to treatment for the complete cure of disease. Patients who are addicted to alcohol/smoking should be targeted with interventions to quit the same, provide free transport facility to RNTCP centres and prompt treatment of ADR, will improve adherence to medication.