The rat retina can be successfully grafted within a long time period which extends into the first 2 weeks of postnatal life. Postnatal grafts taken 1-2 days (PN 1-2) after birth demonstrate no significant differences in their ability to form successful grafts. However, grafting success begins to diminish gradually starting between PN 2-4 and reaches a low point in organization and survival by PN 14. PN 21 grafts rapidly degenerate by 1 to 2 days after transplantation. Although early postnatal retinal tissue can be successfully grafted, E 15 embryonic retinas make better grafts for their ability to form consistent laminae and to integrate with host tissue in a fresh lesion paradigm.