Hair-papilla derived cells were grown in monolayer culture and revealed the typical morphology and growth pattern which was similar but not identical to control fibroblasts. Hair-papilla cells were found to produce considerable amounts of collagen type I and type III and fibronectin. Type IV collagen production could not be detected. The ratio of collagen type III and type I clearly differed from the pattern observed in normal fibroblasts, being much higher in hair-papilla cells, where type III accounted for more than 20% of total collagen synthesis. These data show that hair-papilla derived cells have biosynthetic capacities similar to those of human skin fibroblasts as well as characteristic differences, indicating that they represent a specialized fibroblast subpopulation.