Leukocytes appear to have a central role in the inflammatory response that develops during acute brain ischemia. This brief review adduces evidence that leukocytes accumulate in focal zones of acute brain ischemia at a sufficiently early stage to participate in the process of progressive ischemic brain damage and that partial inhibition of that accumulation, by various measures, can attenuate ischemic brain injury. Mechanisms of leukocyte adhesion are discussed in detail and an inference is put forward that leukocytes are an important factor in progressive ischemic injury, but almost certainly act in concert with a number of other similarly important factors. On this basis, leukocyte inhibition may have demonstrable benefit in acute stroke, but ultimately be found to only partially spare potentially salvageable tissue in the ischemic zone.