The aim of this study was to determine the intensity of Hsp27 protein expression in fibrocystic breast changes (FC) and invasive ductal breast carcinoma (IDC) and to examine its impact on patients' clinico-pathological characteristics and overall survival. Immunohistochemical reactions were conducted on archival samples of 20 cases of FC and 101 cases of IDC treated in 1999-2002. Nuclear-cytoplasmic Hsp27 expression was observed in 92 (92.1%) of the examined cases of IDC, and all the cases of FC. Significantly higher Hsp27 expression was observed in G2 (p < 0.01) and G3 cases (p < 0.0001) compared to FC. HER-2 positive cases had higher Hsp27 expression (p = 0.0153), than HER-2 negative cases. Our research showed that Hsp27 could have an impact on tumor malignancy. Moreover, a positive correlation between the expression of Hsp27 and HER-2 positive cases was demonstrated.