The objective of this study was to evaluate the effect of incorporation of basic fibroblast growth factor (bFGF)-impregnated gelatin microspheres into an artificial dermis on the regeneration of dermis-like tissues. When used in the free form in vivo, bFGF cannot induce sufficient wound healing activity, because of its short half-life. Therefore, sustained release of bFGF was achieved by impregnation into biodegradable gelatin microspheres. A radioisotope study revealed that incorporation of bFGF-impregnated gelatin microspheres significantly prolonged in vivo retention of bFGF in the artificial dermis. Artificial dermis with incorporated bFGF-impregnated gelatin microspheres or bFGF in solution was implanted into full-thickness skin defects on the back of guinea pigs (1.5 cm x 1.5 cm) (n = 4). Incorporation of bFGF into the artificial dermis accelerated fibroblast proliferation and capillary formation in a dose-dependent manner. However, the accelerated effects were more significant with the incorporation of bFGF-impregnated gelatin microspheres than with free bFGF at doses of 50 microg or higher. We conclude that the gelatin microsphere is a promising tool to accelerate bFGF-induced tissue regeneration in artificial dermis.