The immunodetection of HER-2/neu oncogene product was performed in 108 breast carcinomas using immunoperoxidase technique. Monoclonal anti HER-2/neu protein was applied on frozen sections. Immunoprecipitates were evaluated by a computerized system of image analysis (SAMBA). The percentage of the immunostained tissue surfaces and mean optical densities were correlated with the 5 year overall and disease-free survival rates. It was shown that in optimal conditions of antigen preservation and standardized method of immunoprecipitates evaluation, 67% of breast carcinomas were more than 20% pHER-2/neu positive. The pHER-2/neu overexpression was not significantly correlated with the overall 5 year survival. However large positive anti pHER-2/neu surfaces were correlated with higher risk of recurrence (p = 0.0013) and of metastases (p = 0.035).