Samples were taken at biopsies of peripheral lung tissue from patients with and without emphysema. The emphysematous patients were diagnosed as such by lung function tests and clinical history, and affirmed by the pathological anatomy of the resection preparations. The other group comprised patients negative for emphysema in all respects. A number of biochemically important substances were determined quantitatively in the dried, powder and defatted lung tissue. Typical cellular parameters, such as DNA, RNA and protein, were not different in the groups. Neither the soluble nor the buffer-insoluble collagen were quantitatively different in both groups; the individual variation is great. The amount of soluble collagen relative to the insoluble collagen per sample is much less variable; this ratio is the same in both groups as well. The total amount of mucopolysaccharides as measured by the uronic acid content is hardly different in both groups. The relative amount of galactosamine-containing mucopolysaccharides in emphysematous patients is significantly lower than in ‘normals’. This is still more evident if the ratio glucosamine/galactosamine is determined. This ratio is 3.20 for emphysematous patients compared to 0.77 in the non-emphysematous subjects.