This study was undertaken to analyse children with pulmonary cavitatory tuberculosis which is a rare and infectious condition. The pretreatment characteristics, course and response to three different anti-tuberculous regimes in 27 children with cavitary pulmonary lesions registered at the TB Clinic, Institute of Child Health, are described. Male:Female ratio was 1.2:4. Thirty per cent of affected children were below 3 years of age and had predominant lower lobe involvement whereas in older children the upper lobes were affected. Eighty five per cent of children had definite history of contact with an adult with tuberculosis. Tuberculin test was positive in 70% of children. Cavitary lesion were observed in the right lung in 66% of cases. Follow up and surveillance was carried out in 23 children who completed the anti tuberculous treatment. Regimes with isoniazid, rifampicin, pyrazinamide and streptomycin were given to different groups. Response and compliance was also monitored. Eleven out of 23 children had persistence of radiological lesions even after completion of 9 months of therapy. Inclusion of streptomycin with 2 or 3 bactericidal drugs in the intensive phase showed a better response.