Preventive therapy for tuberculosis in children is an important strategy to control pediatric TB in addition to early diagnosis and treatment of infectious cases in the community. In low burden countries, it is an important tool for preventing TB at all ages as the opportunities for re-infection are few. In contrast in high burden countries, preventive therapy though effective in preventing occurrence of disease among infected, can not prevent re-infection--an event of fairly high occurrence in these settings. Children under 5 years of age or immuno-compromised children of any age who have the highest risk of developing infection and disease when exposed are the main focus for preventive therapy in high burden settings. A 6 months therapy with INH continues to be the preferred modality of preventive therapy as efforts are being made to identify a short course preventive therapy using Rifampicin and other drugs.