The incorporation of fibroblasts into a hydrated collagen lattice results in lattice contraction and collagen reorganization to form a dermal equivalent. Lattices fabricated with 7.7 mg collagen and seeded with 1 X 10(5) cells were found to give the best results in terms of their mechanical properties and ability to maintain cell viability. Newly-cast lattices were found to be completely digested by 0.085 units/ml bacterial collagenase in 3 h, whereas after 30 d in culture, limited digestion took place over 24 h. Electrophoretic analysis showed that the proportion of cross-linked collagen in the 30 d lattice was increased by 2.5-fold compared to the initial collagen preparation. These results indicate that a dermal equivalent better suited for grafting may be produced after 20-30 d in culture.