This study was designed to investigate the association between immune inflammation and androgen receptor (AR) expression in benign prostatic hyperplasia (BPH). We retrospectively analyzed 105 prostatectomy specimens. An immune inflammation score for each specimen was defined by combining three immunohistochemical markers (CD4, CD8 and CD20). The immunohistochemical markers were CD4 and CD8 for T lymphocytes, CD20 for B lymphocytes and AR antibody for the AR in BPH samples. Rates of CD4, CD8, CD20 and AR expression in BPH were 20 (19.0%), 21 (20.0%), 101 (96.2%) and 48 (45.7%), respectively. Total prostate volume (TPV) was higher in the immune inflammation group than in the non-immune inflammation group (62.7 ml vs. 49.2 ml, t=2.482, P<0.05). Patients in the immune inflammation group had a higher serum prostate-specific antigen (PSA) than those in the non-inflammation group (7.5 ng ml(-1 )vs. 5.4 ng ml(-1), t=2.771, P<0.05). Specifically, the immune inflammation group showed a higher rate of AR expression than the non-inflammation group (56.1% vs. 28.2%, χ(2)=7.665, P<0.05). Our study revealed a strong association between immune inflammation and TPV, serum PSA and AR expression in BPH tissue. Prostate hyperplasia caused by an immune inflammatory process may contribute to BPH progression over time. Therefore, the inflammatory response involved in BPH may be a prime therapeutic target.