Interleukin (IL) 10 and interferon-gamma (IFN-) levels in induced sputum supernatants of 21 tuberculosis (TB) patients at diagnosis and during chemotherapy were correlated to recurrence rates. IL-10 decreased until day 60 of treatment (T60), and between T60 and T180 it increased again in 7 cases (Pattern 1) and further decreased in 14 cases (Pattern 2). Follow-up of 69 months was performed in 20/21 cases; 6 had recurrence of TB, of which 5/7 (71%) had Pattern 1 and 1/13 (7.7%) Pattern 2 (OR 30.0, 95%CI 2.19411.3, P 0.0072). This was not observed for IFN-. High IL-10 levels at the end of treatment may function as a risk factor for TB recurrence.