A young patient was diagnosed as having Boeck's sarcoid on the basis of chest x-ray studies but had no pulmonary symptoms and performed nearly normally in pulmonary function studies, the only functional "abnormality" being a diffusing capacity 90% of predicted. Because young persons usually demonstrate above-normal values for diffusing capacity in our laboratory, we think that below-normal values in such persons warrant further investigation. Typical cases of Boeck's sarcoid may not include significant symptoms or pulmonary function impairment, but infiltrates may be seen on chest films. Steroids for sarcoid should be reserved for cases of significant disease.