Polymorphonuclear neutrophils (PMN) can recognize, engulf and kill microorganisms and are thus an important host defence against infection. The initial encounter between a microbe and the neutrophil takes place at the neutrophil surface. Receptors, including those for the Fc end of the immunoglobulin G (ref. 1), the C3b component of complement, formyl peptides and plant lectins have been identified on the surface of neutrophils. We have now examined the surface pattern and arrangement of receptors for the plant lectin concanavalin A (Con A) to determine if the surface receptor array varied with the functional state of the neutrophil. We found that receptors for Con A clustered at the front of polarized neutrophils.