The relation between the transport from tissue to blood of radioactive iodide and xenon has been studied in resting and hyperemic dog skeletal muscle in control and in hemorrhagic shock. In resting muscle as well as in hyperemic the transport of iodide was shown to be diffusion-limited above 3–4 ml/min/100 g. Shortly after bleeding a more efficient diffusional transport of iodide was seen at lowered flows; here the flow was the rate limiting factor for transport. As shock progressed there was a change of flow towards values slightly below control but the transport of iodide for any given flow was now 40–50°/o lower than in control. In this state induced hyperemia could increase flow but could not increase transport of iodide. It is concluded that in progressive hemorrhagic shock there is a transport disturbance for small water-soluble molecules which gives a lowered diffusional limit for transport compared to control, and which is reached already at flows of 3–5 ml/min/100 g. The most likely explanation for such a transport disturbance is a more inhomogeneous distribution of flow through the capillary bed which can be caused by intravascular phenomena such as stasis and occlusion.