Purpose: To study the factors influencing sputum smear conversion including Serum C-Reactive Protein (CRP) and its correlation with disease severity in tuberculosis patients. Method: Levels of Serum-CRP concentrations were determined in 60 patients with pulmonary tuberculosis, 30 healthy volunteers and patients in follow-up after completion of antitubercular treatment (DOTS therapy). Results: Serum-CRP levels were found to be significantly higher in smear-positive group as compared with the follow-up patients and smear-negative control group. The values were 43.65 ± 23.68, 9.88 ± 5.23 and 4.04 ± 3.85 mg/L respectively (P < 0.0001). Among the smear-positive patients, Serum-CRP levels were the highest in AFB3+ patients (65.28 ± 10.32) as compared with the AFB2+ patients (35.93 ± 7.22), AFB1+ patients (16.37 ± 2.62) and AFB scanty patients (10.92 ± 2.97) respectively, the difference was found statistically significant (P < 0.0001). Correlation of predictors of sputum smear conversion also revealed that these values were significantly higher in active pulmonary tubercular patients as compared to control. It is also found significant positive correlation between AFB smear positive patients with levels of Serum-CRP concentration. Conclusion: Serum-CRP levels are significantly correlated with disease severity in patients with active pulmonary tuberculosis. Thus these findings from the present study would certainly add new criteria for early diagnosis of TB, which may lead to development of new strategies to treat TB.