P olymorphonuclear neutrophils (PMN) traverse basement membrane to reach sites of infection. We have studied the role of laminin, a specific basement membrane component, in this process using three assay systems. In the Boyden chamber, laminin was found to stimulate chemotaxis of neutrophils while fibronectin did not. Co-incubation of cells with antibody to laminin blocked this chemotaxis, while antibody to fibronectin was without effect. In the human amnion system, neutrophils were shown to penetrate through the tissue when the peptide chemoattractant f-Met-Leu-Phe was placed on the opposing side. Antibody to laminin, but not to fibronectin, blocked this penetration. In an attachment assay system, laminin, but not fibronectin, was found to increase dispase-treated neutrophil attachment to type IV (basement membrane) collagen-coated plastic and to a plastic substrate itself. Electrophoretic analysis of PMN extract indicated the presence of laminin, and indirect immunofluorescence suggested that laminin is localized on the surface of the neutrophils. These data suggest that PMN can bind laminin on their cell surfaces, use laminin to attach to basement (type IV) membrane collagen, and migrate toward a gradient of laminin. These properties may be important for the passage of neutrophils from the circulation to sites of infection.