Urinary hormone excretion patterns were studied in 55 lung cancer patients, 45 sick controls with pulmonary emphysema and 59 well controls, all men. The patterns included estrone, estradiol, estriol, androsterone, etiocholanolone, 11‐oxygenated‐17‐ketosteroids, beta fraction, pregnanediol, Porter‐Silber chromogen, 17‐ketogenic steroids and the biological activity, protein content and carbohydrate content of the gonadotropin residue. Lung cancer patients were classified by cell type into adeno, squamous and anaplastic carcinoma. The mean urinary hormone pattern for each cancer cell type and for emphysema was compared with that for the well individuals. Analysis using linear discriminant function showed that each sick group had an abnormal and distinctive pattern as compared to the normals. The findings suggest that changes in the endocrine system are associated with the particular type of lung cancer present and to a lesser degree with emphysema. This is of particular interest in a disease of an organ usually considered to be independent of endocrine control.