Background: Treatment delays increase adverse treatment outcome of tuberculosis (TB). It is necessary to identify reasons behind such delays in different phases of anti-TB treatment (ATT). Objective: To study treatment seeking behavior (TSB) and risk factors for treatment delays among TB patients. Materials and Methods: New smear positive (NSP) pulmonary TB patients initiated on category one regimen of directly observed treatment short course (DOTS) at 24 DOTS centers (N = 156) in E-ward of Mumbai Municipal Corporation (MMC) were interviewed using pre-tested semi-structured schedule, which was designed to elicit the TSB and factors associated with treatment delays. Results: Median duration of cough with expectoration before consulting a provider was 8 weeks (min = 1, max = 96 weeks). Risk factors for patient delay were age <45 years, living without family. Mean provider delay was 17.91 (SD = 18.026, range = 7-99 days). First approach to the private sector for the treatment was associated with provider delay. Mean delay to start continuation phase (CP) was 18.46 days (SD = 16.292) (min = 4 days, max = 67 days). Delay to go for sputum microscopy, to collect reports, delay in reporting, supposed that treatment is completed as felt better were the reasons to delay to start CP. It was associated with migration, smoking, alcoholism, living away from family, social stigma involving hiding the disease from spouse and relatives. Conclusion: Risk factors identified for treatment delays were age <45 years, lack of family support, first approach to the private sector, migration, addictions and social stigma. Strengthening Revised National TB Control Program by operational research to involve the private sector, improving transfer procedures for migrants, creating public awareness to remove stigma and transport of patients and/or their sputum samples from DOTS centers to microscopy centers may be considered to decrease treatment delays.