Objectives: The present study explores who are those people discontinued from DOTS regime, had irregular compliance and why it happened so. Methods: The study was conducted in 36 DMCs from 12 TUs of three districts in West Bengal, India. Information was collected from two groups – 590 DOTS defaulters from treatment registers and directly from 74 DOTS defaulters. Excluded people are those who were put on DOTS but did not complete full treatment or had anytime become defaulter. Factors were explored on the reasons of retrieval or non-retrieval of DOTS defaulter group and why a few persons became early defaulters and others late defaulters. Results: Results indicated that only 12.4% could have been retrieved into DOTS treatment. Retrieval is influenced by literacy, employment and caste. Among defaulter respondents, knowledge about symptoms of tuberculosis is very poor. Percentages of higher stigma level (28-44) were more (62.2%) compared to lower stigma level (0-27) (37.8%). Mean duration of persons on DOTS is 26.9 days. Early defaulters (3-27 days) are 47.3% compared to delayed defaulters (28-90 days) 52.7%. People who have started DOTS have better knowledge and positive attitude towards health services meant for RNTCP. No socio-economic factors have significant relationship with the non-adherence to DOTS. However, long term therapy, side effects of drugs, no remedies for side effects, poor welcoming attitude of service providers are determinants of non adherence. Conclusion: Finally the outcome of the present study recommends undertaking an in-depth study to explore causes of exclusion from adherence to DOTS when conventional determinants have been proved non-significant.