Type IV collagen and laminin, major components of the basement membrane, are involved in several biologic activities. In malignant tumors, cell-matrix interactions are very important for tumor invasion and metastasis. In hepatocellular carcinoma, these matrices are present around hepatoma cells. However, there is little known how these matrices influence on the behavior of hepatoma cells. In this study, we investigated the participation of type IV collagen and laminin in the motility, adhesion, and proliferation of hepatoma cells using three different human hepatoma cell lines (KYN-1, 2, 3). The production of type IV collagen and laminin was investigated by immunoelectron microscopy. The effects of type IV collagen and laminin on hepatoma cell migration, adhesion, and proliferation were evaluated by the haptotactic migration assay, phagokinetic track assay, an adhesion assay, and a 3H-thymidine incorporation assay. Immunoelectron microscopy showed the production of type IV collagen and laminin by hepatoma cells. Type IV collagen and laminin enhanced haptotactic migration, chemokinesis, adhesion, and thymidine incorporation by hepatoma cells. The combination of type IV collagen and laminin had the most pronounced effects on these biologic activities. These results indicate that type IV collagen and laminin promote hepatoma cell motility, adhesion, and proliferation in an autocrine manner, suggesting enhancement of invasion and metastasis of hepatoma cells by these basement membrane components in vivo.