The purpose of this study was to determine relationship between HER-2/neu status and estrogen receptor, progesterone receptor, grade and age by comparing fluorescence in situ hybridization and immunohistochemistry. One hundred invasive breast carcinomas were reviewed and fluorescence in situ hybridization analysis was performed in all cases. Immunohistochemical scores showed a perfect concordance with fluorescence in situ hybridization amplification ratios (p < 0.0001). The results indicated a significant correlation between HER-2/neu and grade, but an inverse relationship between HER-2/neu and hormone receptors. In women aged ≤ 45 years, an inverse relationship between HER-2/neu and progesterone receptor was found and no association was noted between HER-2/neu and other factors. In women aged > 45 years, the results indicated a significant correlation between HER-2/neu and grade, and there was an inverse relationship between HER-2/neu and hormone receptors.