The prognosis of oesophageal cancer patients is related to the portion of MIB-1 positively stained tumour nuclei. In this study, an image analysis system was developed based on LEICA Image Processing and Analysis System to reduce the subjective, tedious and inaccurate manual counting of nuclei staining. Representative oesophageal cancer tissues were collected and immunohistochemical preparations of MIB-1 were made. The MIB-1 positive nuclei in these tumours were assessed by quantitative counting, semi-quantitative counting, and three computer assessment methods using . Our results showed that computer assessment methods were reliable and consistent. The procedure using the system could be accomplished within 15 min. Overlapped or missed counting of nuclei by the observer were eliminated. The image analysis system can really assist experts in obtaining reliable data for the prognosis of oesophageal cancer patients quickly.