The authors investigated the expression of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) during skin wound healing using immunohistochemical techniques. After a full-thickness incision was made on the dorsal skin, mice were killed 0.5, 1, 3, 8, 24, 72, 144, or 240 hours after incision, and the wound was excised. To evaluate the influences of postmortem degeneration, cutaneous wound excision was performed 1 to 5 days after the mice were killed. The excised wounds were stained by the conventional streptoavidin-biotinylated peroxidase complex method, using specific antibodies, and the ratio of the number of positive cells to total cells was determined. Expression of bFGF was detected in the nuclei of epidermal cells and fibroblasts in the early 0.5- to 1-hour phases and the late 24- to 144-hour phases. Expression of VEGF was detected in the cytoplasm of epidermal cells in the 24- to 144-hour phases. Immunoreactivity of both cytokines was detected 1 day post mortem and was especially well preserved in the fibroblasts. Time-dependent expression of both factors suggested that they would be useful markers for the determination of wound age. However, bFGF should be superior to VEGF because of its earlier expression and because of its more persistent expression in dermal fibroblasts with increasing postmortem interval.