The clinical and radiological features in 38 infants less than 3 months of age with tuberculosis proved by culture are described and may aid early diagnosis of this often fatal condition. Respiratory symptoms, cough in 33 (87%) and tachypnoea in 31 (82%), were the commonest presenting symptoms. Twenty five infants (66%) had hepatomegaly and 20 (53%) splenomegaly. Mantoux testing gave an induration of > 15 mm in three of 17 (18%) infants. In a further five a Tine test gave confluent response. Chest radiography in 27 infants showed miliary tuberculosis in seven (26%) and hilar or paratracheal adenopathy in 14 (52%) and 10 (37%) respectively. Compression of either the bronchi or trachea or both was noted in 15 (56%). Detection of this complication was aided by high kilovolt radiographs. A culture of Mycobacterium tuberculosis was obtained from gastric aspirate in 35 (92%) infants, but positive cultures were also obtained from cerebrospinal fluid, tracheal or bronchial aspirate and liver and lymph node biopsy. Of 30 mothers evaluated seven (23) had previously unsuspected pulmonary tuberculosis.