BACKGROUND To evaluate tuberculosis screening and efficacy of prophylaxis in contacts of patients with pulmonary tuberculosis. METHODS A total of 7453 contacts of 1909 patients with pulmonary tuberculosis treated at four tuberculosis dispensaries located in Istanbul, between 2005 and 2009 were included in this retrospective screening-based study. Data on demographics, smear positivity, PPD positivity, rate and onset of secondary tuberculosis and prophylaxis were recorded in contacts. RESULTS Overall 184 (2.5%) secondary cases of tuberculosis were identified within a mean 2.9 (1-5) years of follow-up. The rate for secondary tuberculosis was 3.1% (163/5335) in smear positive and 1.0% (20/2118) in smear negative contacts. With and without prophylaxis rates for secondary tuberculosis after 6 months of index case was identified in 0.7% (6/912) and 2.0% (9/455) of contacts aged 0-15 years, in 0.9% (3/339) and 2.8% (51/1826) of contacts aged 16-35 years and in 0% (0/215) and 0.9% (14/1507) of contacts aged ≥ 36 years, respectively. CONCLUSIONS In conclusion, our findings indicate high risk of being infected and diseased in smear positive contacts along with efficacy of prophylactic therapy among contacts not only in the childhood but also in adults, particularly in contacts aged 16-35 years.