Purpose To evaluate the correlation of retinal thickness between optical coherence tomography (OCT) images and histologic slides ． Methods Retinal thickness was measured in 16 rabbit retinal histologic slides．The same eyes were previously viewed by OCT for the comparison of results between two methods．Retinal thickness of each OCT image section was measured using both the manually assisted (requiring observer localization of reflectivity peaks) and the automated modes of the computer software． Results Retinal thickness as measured by OCT demonstrated a high degree of correlation with retinal histologic study．The automate d method (gamma;=0．66，P＜0.01) was less reliable than the manually assisted one (gamma;=0．84，P＜0．001)．The former had an error in 95% confidence interval，ranged in-0.71～11.09 mu;m，the latter had a less error，ranged in-2.99～5.13mu;ｍ． Conclusion Retinal thickness can be quantitatively measured by OCT examination．However，computer automatic identification of the reflective boundaries may result in errors in some cases．To measured the retinal thickness by manually assisted mode can increase the degree of accuracy． (Chin J Ocul Fundus Dis，2000，16：71-138)