1. In contrast to collagen from the aponeurosis of normal adult subjects, the nodules, contractures and apparently unaffected aponeurosis from patients with Dupuytren's disease contained substantial amounts of type III collagen. 2. The presence of type III collagen supports the previous proposal that the initial response to injury is the synthesis of an increased proportion of this form of collagen. The increased amounts in the apparently unaffected aponeurosis indicate the disease is not strictly focal but more systemic than is usually considered.