Objective To investigate hypoxia-inducible factor 1α (HIF-1α) protein expression in normal prostates (NP), benign prostatic glandular hyperplasia (BPH), and prostate adenocarcinoma (Pca).Methods HIF-1α protein expression was determined by immunohistochemistry in formalin-fixed and paraffin-embedded specimens obtained from 13 cases of NP, 28 cases of BPH, and 34 cases of Pca. In cases of Pca, the relationship between HIF-1α protein expression and certain clinicopathological factors, such as clinicopathologic stage and Gleason score, was evaluated. Results NP manifested no immunoreactivity, whereas Pca and BPH showed significantly increased HIF-1α protein expression. A significantly higher expression was observed in Pca specimens compared with BPH samples. In Pca, no significant relationship between HIF-1α protein expression and clinicopathological factors was found. Conclusion Our findings of increased HIF-1α protein expression in BPH and Pca specimens suggests the potential role of this protein in BPH and Pca. Objective To investigate hypoxia-inducible factor 1α (HIF-1α) protein expression in normal prostates (NP), benign prostatic glandular hyperplasia (BPH), and prostate adenocarcinoma (Pca). Methods HIF-1α protein expression was determined by immunohistochemistry in formalin- In cases of Pca, the relationship between HIF-1α protein expression and certain clinicopathological factors, such as the clinicopathologic stage and Gleason score, was significantly higher than HIF-1α protein expression. A significant higher expression was observed in Pca specimens compared with BPH samples. In Pca, no significant relationship between HIF-1α protein expression and clinicopathological factors was found. Conclusion Our findings of increased HIF-1α protein expression in BPH and Pca specimens suggests the potential role of this protein in BPH and Pca.