Acute and chronic respiratory diseases amount to a remarkable portion of all cases and days of disability. The systematic care especially for the chronic respiratory diseases has become the task of the Out Patient Departments of Pulmonary Diseases and Tuberculosis in cooperation with the general practitioners and physicians for industrial medicine. The diagnostics of chronic respiratory diseases among which more than the half of all cases gets to chronic bronchitis, pulmonary emphysema and bronchial asthma has still to be qualified. Function testing allows to subdivide chronic bronchitis in nonobstructive and obstructive forms and to gain measurable and comparable assessments of cardiopulmonary limitations of efficiency. By oxyergotensiometry and examination of the diffusion capacity disturbances of ventilation, perfusion and diffusion and combinations of these can be analyzed by blood-gas analysis, ergometric examination and testing of diffusion capacity. Those investigations can be supplemented by determination of breathing mechanics. The development of cardiorespiratory function testing will take place step by step in different levels of accomplishment. These levels have to cooperate for getting an optimal picture of a disease. The extension of the methods of pulmonary function testing in the lung hospitals and the chest clinics since 1970 is reported.