Pulmonary function (VC, FEV1, RV) was assessed in patients with pulmonary tuberculosis discharged in 1958/59 as cured or markedly improved. According to FEV1/VC% the patients were divided into 40 obstructive and 59 non-obstructive cases and the tests were repeated by the same method in 1974. The control included physical and X-ray examinations, a questionnaire and the assessment of airway resistance (Rt). In the non-obstructive group the change in VC in 15 years was only -27.7 ml/year, in the obstructive group, -54.3 ml/year. There was little difference between the two groups in the diminution of FEV1 (28.8 and 35.3 ml/year, respectively). The material was subdivided into surgically and drug treated groups and studied statistically. The only significant change of function in the surgically treated group was in RV, whereas in the other group nearly all of the functional changes were significant statistically.