Vertically acquired HIV infection is becoming increasingly common in India. The main clinical manifestations of HIV in childhood are growth failure, lymphadenopathy, chronic cough and fever, recurrent pulmonary infections, and persistent diarrhoea. Pulmonary disease is the major cause of morbidity and mortality in pediatric AIDS, manifesting itself in more than 80% of cases. The most common causes are Pneumocystis carinii pneumonia (PCP), lymphocytic interstitial pneumonitis (LIP), recurrent bacterial infections which include bacterial pneumonia and tuberculosis. The commonest AIDS diagnosis in infancy is PCP, presenting in infancy with tachypnea, hypoxia, and bilateral opacification on chest-X-ray (CXR). Treatment is with cotrimoxazole. LIP presents with bilateral reticulonodular shadows on CXR. It may be asymptomatic in the earlier stages, but children develop recurrent bacterial super infections, and can progress to bronchiectasis. LIP is a good prognostic sign in children with HIV infection in comparison to PCP. HIV should be considered in children with recurrent bacterial pneumonia, particularly with a prolonged or atypical course, or a recurrence after standard treatment. Pulmonary TB is common in children with HIV, but little data is available to guide treatment decisions. Much can be done to prevent PCP and bacterial infections with cotrimoxazole prophylaxis and appropriate immunisations, which may reduce hospital admissions and health care costs.