This chapter presents a rapid method to disperse rat retinas enzymically and separate large quantities of various cell types by centrifugation through a Metrizamide density gradient. This method has been useful for biochemical and pharmacological characterization of several types of retinal cells. Using phase-contrast microscopy, the neurons are primarily rounded and could not be identified without further biochemical characterization photoreceptor cell outer rod segments and may be used as a biochemical marker for these cells. Data describing the biochemical characterization of the whole retina are difficult to interpret because of the heterogeneity of cell types. Consequently, the isolation of enriched populations of purified retinal cells represents a breakthrough in the studies of retinal cell function. The technique for isolation of retinal cells involves chemical dispersion of whole retina using collagenase followed by nonequilibrium centrifugation through a Metrizamide continuous density gradient. This technique has several advantages: large quantities of cells are recovered, enabling thorough biochemical characterization of the cells, and the dispersion is rapid (the cells are exposed to collagenase for 12 min).