Objective To study the progressive development of the retinas through an observation on the histological changes of the retinas from neonatal mice of different day-ages. Methods The retinas from the mice of 1 to 20 days of age were examined by light microscopy,and from 1 to 3 days,by autoradiography. Results The retinas of the mice below 3 days of age only had the RPE cells layer,the neuroblast layer and the ganglion cell layer.With the increase in dayage,the retinas developed gradually and would be mature in the 20th day. Conclusions The retinas of mice is a kind of immature tissue before the 20th days,so it can be considered as transplantation donors. (Chin J Ocul Fundus Dis, 1999, 15: 174-176)