Fibrocytes contribute to wound healing and are uniquely defined by coexpression of hematopoietic and mesenchymal cell markers. In this study, trafficking of fibrocytes was determined in a murine model of colitis induced by administering 3% dextran sodium sulfate (DSS) for seven days. Colonic tissues were immunostained for CD45, collagen type I (Col I), and alpha-SMA. On day 0, there were no CD45(+)Col I(+) cells in colonic tissues. However, on day 7 when inflammatory cells showed remarkable accumulation, oval-shaped CD45(+)Col I(+) fibrocytes were obvious in the submucosal layer. On day 14 when colonic tissues were in the healing phase, numerous spindle-shaped CD45(+)Col I(+) fibrocytes were observed. Emergence of CD45(+)Col I(+) fibrocytes preceded the appearance of alpha-SMA(+) myofibroblasts. Oval-shaped fibrocytes recruited as early as the inflammatory phase of colitis are likely to differentiate into spindle-shaped fibrocytes in the healing phase, suggesting that fibrocytes may promote wound healing in inflamed colonic tissues.