Background: Limited data are available on predictors of persistent sputum smear positivity at the end of second months of anti-tuberculosis (TB) treatment in Ethiopia. The present investigation was undertaken to identify predictors of sputum smear conversion at the end of second months of anti-TB among new smear positive pulmonary tuberculosis patients on treatment in Addis Ababa, Ethiopia. Methods: Case-control study was performed in Addis Ababa public health centers from December 6/2012-January 30/2013. Cases were 78 sputum smear positive TB patients with positive sputum smear at the end of second months of anti-TB, randomly selected from a sampling frame. Two controls were recruited for each case from the same health facility and nearest date of diagnosis to each case with negative sputum smear at the end of second months of anti- TB treatment. Data were collected using a pre-tested questionnaire by trained data collectors. Data was entered using EPI-Info version 3.5.1 and analyzed using SPSS version 20. Odds Ratio & 95% Confidence Interval (CI) used to measure the associations. Results: After adjustment for potential confounders, male (OR=2.13; 95%CI: 1.11-4.08, P=0.023), current smoker (OR=3.38; 95%CI: 1.25-9.14, P=0.017), Absence of BCG scar (OR=2.54;95%CI: 1.33-4.88, P=0.005), low BMI(<17kg/m2)(OR=4.61; 95%CI: 2.04-10.38, P< 0.001), HIV positivity (OR=2.64;95%CI:1.28-5.46, P=0.009) were associated with sputum non-conversion at the end of second months of treatment. Conclusion & Recommendations: The TB control program needs to give special attention to those with the identified risk factors. Closer follow up of patients with the risk factors is essential to have a better TB treatment outcome.

Keywords: Tuberculosis, Sputum smears conversion, 2nd months of treatment