Perforator flaps are widely used in reconstructive surgery, but little is known about the hemodynamic changes within these flaps. Recently, the blood velocity in the perforator artery was shown to be higher than that at the source vessel. This study was carried out to demonstrate the effect of this increased velocity within the perforators in the cutaneous microcirculation of the perforator flap. Twenty-six consecutive patients who underwent unilateral immediate breast reconstruction with deep inferior epigastric perforator (DIEP) flaps were selected. A 3-stage prospective study using 2 laser Doppler probes was carried out. Stage 1: preoperative measurements; Stage 2: immediate postoperative measurements; Stage 3: postoperative measurements after 3 months. Statistically significant increase of blood velocity in the microcirculation of DIEP flaps was demonstrated in stages 2 and 3 when compared with stage 1 (P < 0.01, Friedman and Wilcoxon tests). The higher blood velocity within the perforator flap microcirculation may be a favorable rheologic feature of perforator flaps.