Recent developments in tissue culture technology permit the mass cultivation of anchorage-dependent cells in a compact and easily maintained system by utilizing the large surface area of suspended microspheres for cellular attachment and proliferation. The present study describes the successful cultivation of pure bovine iris pigment epithelium and mixed bovine retinal pigment epithelium-choroid by microcarrier suspension culture. Ocular pigment epithelial cells were collected from enucleated calf eyes and cultured in conventional monolayer fashion on flat plates. Subsequently, cells were harvested by trypsinization and were inoculated into microcarrier culture. Confluence was obtained in 8 to 12 days and final cell densities were 1 x 10(6) cells/ml for iris pigment epithelium and 8 x 10(5) cells/ml for combined retinal pigment epithelium–choroid; the microcarrier density was 5 gm/L. Samples from ongoing microcarrier cultures were processed for light and electron microscopic examination. Culture of bovine ocular pigment epithelial cells by microcarrier suspension technique provides a simplified method of cultivation of large numbers of cells, with additional advantages in ongoing culture maintenance and accessibility.