Insulin-like growth factor-1 (IGF-1) and its primary binding protein-3 (IGFBP-3) play an important role in cellular proliferation, differentiation and apoptosis in many tumors, including breast cancer (BC). The objective of this study was to determine the clinical significance of the serum levels of IGF-1 and IGFBP-3 in BC patients. A total of 96 patients with a pathologically confirmed diagnosis of BC were enrolled into this study. Serum IGF-1 and IGFBP-3 levels were determined by the solid-phase sandwich enzyme-linked immunosorbent assay (ELISA) methods. Age- and sex-matched 30 healthy controls were included in the analysis. The median age of diagnosis was 48 years (range: 29-80). Thirty-seven (39 %) consisted of metastatic disease. No significant difference in baseline serum was found in both IGF-1 and IGFBP-3 levels between BC patients and healthy controls (p = 0.92 and p = 0.26, respectively). None of the prognostic parameters analyzed was correlated significantly with the serum assay concentrations. Likewise, no correlations were also found between these serum concentrations and response to chemotherapy. No significant correlation was found between serum IGF-1 and IGFBP-3 levels in BC patients (r (s) = 0.048, p = 0.66).The patients with elevated serum IGF-1 levels had favorable in survival than those with lower levels (p = 0.05). However, serum IGFBP-3 concentrations were found no prognostic role for outcome (p = 0.35). In conclusion, elevated serum IGF-1 level is afavorable prognostic factor for overall survival in BC patients.