Mediastinal lymphadenopathy is a prominent feature of adult tuberculosis in immigrant groups in the United Kingdom. Chest radiography of 95 tuberculous immigrants showed mediastinal gland enlargement in 29 cases, whereas none of the 42 Europeans showed this feature. An analysis has been made of the distribution of the disease in all groups together with a more detailed evaluation of mediastinal involvement in the immigrants. Pericardial effusions were seen in eight patients together with the following three unusual complications: (1) broncho-oesophageal fistula; (2) bronchial erosion; (3) superior mediastinal obstruction.