OBJECTIVES: The study aimed to document the duration of tuberculosis (TB) treatment, and its relationship with the characteristics of the patients. METHODS: This prospective follow-up cohort study was conducted at the chest clinic of Penang General Hospital between March 2010 and February 2011. Medical records and TB notification forms of all new smear positive pulmonary tuberculosis (PTB) patients, who were diagnosed during the study period, were reviewed to obtain socio-demographic and clinical data. Based on the standard guidelines, the normal benchmarks of treatment duration for the intensive- and continuation phase of TB treatment were taken as 2 and 4 months, respectively. A patient in whom the clinicians decided to extend the intensive phase (IP) for ≥ 2 weeks was categorized as a case of prolonged IP. The same criterion applied for the continuation phase (CP) of the treatment.  RESULTS: Out of the total 336 patients, 261 completed the IP of the treatment. Subsequently, 226 completed the CP. The average duration of TB treatment (n = 226) was 8.19 (SD 1.65) months. 49.4% (129 out of 261) patients completed the IP in 2 months, whereby only 37.6% patients (85 out of 226) completed the CP of the treatment in 4 months. In multiple logistic regression analysis, being a smoker, body mass index less than normal and a history of ≥ 4 weeks cough were the predictors of longer duration of the IP, while diabetes mellitus and presence of lung cavities were the only predictors of longer duration of the CP of the treatment.  CONCLUSIONS: The average duration of treatment in new smear positive PTB patients was longer than the targets set by World Health Organization. There is lacking a uniform international criterion to evaluate how well National Tuberculosis Program of Malaysia has performed in terms of managing duration of treatment in PTB patients.