Fibrin has been used extensively in cell encapsulation because it has important biological properties. Keratinocyte encapsulation in fibrin is a widely used technique in skin tissue engineering. The production of growth factors (EGF, TGF-beta1 and PDGF-BB) was evaluated when keratinocytes are encapsulated in fibrin. Secretions of TGF-beta1 and PDGF-BB increased more than five times compared to monolayer cultures. Encapsulated cells secreted about 80% active form of TGF-beta1 (monolayer cells only secreted inactive form). An enhanced secretion of TGF-beta1 and PDGF-BB was found in encapsulated cells, showing that fibrin capsules are favourable for the production of these growth factors.