Laminin-10/11, the laminin isoforms containing the α5 chain, are major components of basement membranes of many fetal and adult tissues. Laminin-10/11 purified from the conditioned medium of human lung carcinoma cells were potent in mediating adhesion of the carcinoma cells in an integrin α3β1-dependent manner. To further define the type(s) of integrins involved in cell adhesion to laminin-10/11, we examined the effects of a panel of function-blocking anti-integrin antibodies on the adhesion of different cell types to laminin-10/11. Although anti-integrin β1 antibody inhibited the adhesion of all cell types tested, anti-α3 antibody inhibited the adhesion of carcinoma and glioma cells but not fibroblastic cells. Adhesion of fibroblastic cells was inhibited, however, by a combination of anti-α3 and anti-α6 antibodies, suggesting that both α3β1 and α6β1 integrins function as laminin-10/11 receptors in these cells. To explore this possibility, we examined the adhesion of K562 leukemic cells transfected with integrin α3 or α6 subunit to laminin-10/11 or other laminin isoforms. Laminin-10/11 were potent adhesive ligands for both the α3β1 and α6β1 transfectants, whereas laminin-5 was the preferred ligand for the α3β1 transfectants. Upon stimulation with the activating anti-integrin β1 antibody, both transfectants became more adherent to the substratum regardless of the type of laminins coated, although their preference for laminin isoforms remained unaltered. K562 cells transfected with α6 and β4 subunits were also capable of adhering to laminin-10/11, indicating that integrin α6β4 is another receptor for laminin-10/11. Even with lung carcinoma cells, the α6-containing integrins partly contributed to adhesion to laminin-10/11 at higher coating concentrations, although non-integrin receptor(s) might also be involved under such conditions. These results indicated that laminin-10/11 are potent and versatile adhesive ligands in basement membranes capable of binding to both α3β1 and α6β1 integrins with high avidity and also to α6β4 integrin.