This study was undertaken to localize fibronectin and type IV collagen in the cultured retinal pigment epithelial cell by means of immunofluorescent staining and immunocytochemical methods. Immunofluorescent staining and immunocytochemical methods revealed fibronectin and type IV collagen localized on the extracellular membrane of the cultured retinal pigment epithelial cell. Ultrastructural immunocytochemical technique also revealed fibronectin associated with extracellular tissue. This study demonstrated that fibronectin and type IV collagen are an integral component of the extracellular matrix of the human retinal pigment epithelial cell in vitro.