Objective To evaluate the clinical significance of serum levels of insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP-3) in the diagnosis of prostate cancer (PCa), as well as the significance of their combination with prostate-specific antigen (PSA) and free PSA (fPSA). Methods The serum levels of IGF-1, IGFBP-3, PSA and fPSA were measured with chemoiluminescence immunoassay (CLIA) in 52 patients of pathologically identified prostate cancer, 48 cases of benign prostatic hyperplasia (BPH) and 48 healthy individuals. Results The serum levels of IGF-1 was significantly higher in the PCa group than in the BPH and healthy control groups (P＜0.01). However, there was no statistically difference in the IGF-1 level between BPH and healthy control groups (P＞0.05). The serum concentration of IGFBP-3 was significantly lower in the PCa group than in the BPH and healthy control groups (P＜0.01), and there was also significant difference between BPH and healthy control group (P＜0.01). IGF-1 and IGFBP-3 had the sensitivity of 83.6% and 76.4% in the diagnosis of PCa respectively, and specificity of 84.0% and 74.0%, positive prediction value of 85.2% and 76.4%, and negative prediction value of 82.4% and 74.0%, respectively. Combined detection of serum levels of IGF-1 and PSA/fPSA increased the sensitivity of diagnosis significantly. Conclusion Serum levels of IGF-1 and IGFBP-3 are quite different in PCa patients when compared with normal healthy control. Combined application of IGF-1 and PSA or fPSA enhances their clinical value in diagnosis of PCa.