In the present study laser Doppler flowmetry was used to evaluate skeletal muscle perfusion before and after acute hindlimb ischemia in rats. Three laser Doppler microprobes were placed in the anterior tibial muscles of both legs. Six animals were used as non-ischemic controls and 22 animals were subjected to complete ischemia in the left hindlimb for 0.5 to 4.5 hr. By calculating a perfusion index based on recordings from the left and the right leg, a continuous measurement of relative perfusion could be performed. Reactive hyperemia was demonstrated after ischemia of shorter than 2 hr duration. After longer occlusion periods, the reperfusion decreased with increasing duration of ischemia. It is concluded that the use of laser Doppler microprobes offers possibility for continuous evaluation of relative microvascular blood flow in normal and postischemic skeletal muscle, and that the technique would be useful in experimental studies concerning ischemia-reperfusion injury of skeletal muscles.