Abstract： Objective To determine the occurrence of cell dea th in situ in diabetic-like retinopathy from the streptozotocin (STZ)-induced diabetic rats after 6, 9, 12 months. Methods 90 male Sprague -Dawley rats were randomly divided into normal control group (n=30) and dia betic model group. STZ were used to induce diabetes in rats. Rats in each grou p were frequently examined with blood glucose and weight, and killed after 6, 9, 12 months(n=20). The sections prepared from the trypsin-digested retina w ere studies with periodic acid-schiff-hematoxylin stain. The terminal deoxynuc leotidyl transferase-mediated dUTP nick end labeling (TUNEL) reaction was used to detect the preferentially apoptotic DNA fragmentation. Results Retinal microvessels of 6 month diabetic rats showed TUNEL-positive pericy tes, which were absent in control rats. Retinal micrographs of 9, 12 month diab etic rats showed pericytes and endothelial cell apoptosis respectively with TUNE L reaction and PAS stain. At 12 months, the numbers of apoptotic endothelial ce lls were more, and each of the pictures showed TUNRL-positive endothelial cell or apoptotic bodies under the light microscope. Conclusions These findings indicate that diabetes leads to the accelerated death in situ of pericyte in the early stages of retinopathy, and with the advance of disease th e endothelial cell apoptosis occurs.