Limitations of the study include: firstly, some patients did not have sputum smear results because the process of grading, capturing and monitoring of sputum smear results as part of routine **data** commenced only during the period 2004-2005; secondly, there is potential misclassification of the outcome variable as culture investigations were not considered; thirdly, it was not possible to establish the reasons for delay in commencing TB treatment after diagnosis; fourthly, findings relating to HIV status should be interpreted with caution as the HIV results were not recorded for most of the patients due to the aforementioned reasons; and fifthly, the study was based only on the routinely collected **data** and therefore did not consider other important variables that could influence the outcome variable, including chest radiograph results, patient symptoms at diagnosis, as well as nutritional status. Nonetheless, as far as could be established, this is the first study in South Africa which has assessed the determinants of two-month sputum smear non-conversion using routinely recorded patient information.