Abstract
Examination of the post-mortem records of 1,391 unselected cases showed that the commonest condition associated with excessive diffuse enlargement of the kidneys was chronic cor pulmonale. A less striking enlargement was found in some cases of chronic rheumatic heart disease. A hypothesis is put forward in which the renal enlargement is regarded as a work hypertrophy brought about by the kidneys' efforts to compensate for a chronic respiratory acidosis.