The development of the ferret retina was studied with light and transmission electron microscopy from prenatal day 21 (E21; midgestation), through postnatal day 33 (P33; eye opening). Tissue samples were taken from the posterior pole of the retina. At E21, the optic cup was completely formed, the pigment epithelium was a single cell layer and the sensory retina consisted of an inner marginal layer and an outer layer of neuralblastic cell perikarya. Mitotic figures were observed among the nuclei of the outermost layer of neuralblastic cells through P10. At E27, the layer of neurablastic cell perikarya was divided into inner (light-staining) and outer (dark-staining) layers. The inner layer, presumbbly ganglion cells, was separated from the outer dark-staining layer at E36; at, E39, a distinct ganglion cell layer and inner plexiform layer was present. At birth light-staining nuclei each with a central dark-staining nucleolus were observed among the nuclei of the outermost layer of neuralblastic cells; these nuclei were presumed to be developing cone cell nuclei. At P2 light-staining nuclei, presumably horizontal cells, appeared within the remaining layer of neuralblastic cell perikarya. Conventional synapses were seen in the inner plexiform layer on P4. Separation of the layer of neuralblastic cell bodies into inner and outer nuclear layers was evident, on P9; by P12, the layers were clearly separated by the outer plexiform layer. Synaptic ribbons appeared in the outer plexiform layer on P12 and in the inner plexiform layer by P15. At the beginning of the second postnatal week (P15) membranous disks were seen in some photoreceptor cell outer segments. Vasculature was not observed prenatally; however, by the fifth week postnatally capillaries were observed as deep as the inner nuclear layer. From this study it is evident that, the ferret retina provides an easily obtainable postnatal tissue at an early stage of development.