Various studies have reported a relationship between c-erbB-2 and c-myc expression and established prognostic indicators, as well as the clinical course in breast cancer patients. In this report ninety paraffin-embedded breast cancer tissue samples were analysed for detecting the expression of the c-erbB-2 and c-myc oncogene by immunoperoxidase-avidin-biotin technique. c-erbB-2 cell membrane staining was observed in 32,2% of the cases and was found to be related to tumor size 37,7% histopathologic types and grade 60% and node-positive patients 37,8%. c-myc cell membrane staining was observed in 93,3% and there was no association with tumor size, tumor type, grade and nodal status. There was no correlation between c-myc amplification and unfavourable clinical outcome. In this study, immunohistochemical expression of c-erbB-2 proto-oncogene product was correlated to tumor characteristics associated with unfavourable clinical outcome,i.e. large tumor size, poor differentiation of the tumor cells and nodal status.