Objective To evaluate the prognostic value of pretreatment neutrophil to lymphocyte ratio (NLR) on prostate cancer patients treated with maximal androgen blockade (MAB).Methods The clinical data of 249 prostate cancer patients treated with MAB in our hospital from October 2007 to March 2017 were retrospectively analyzed.Among all the patients,the median age was 72 years old (ranged 48 to 89 years).The BMI was 14.5-31.8kg/m2 (median 23.0 kg/m2).The PSA was 1.00-758.21 ng/ml (median 60.04 ng/ml).216 patients' tumor invaded surrounding tissues;lymph node metastasis occurred in 157 patients;and distant organ metastasis occurred in the remaining 174 patients.The Gleason score was 3-10 (median 7).Copfimary end points were progression-free survival (PFS) and cancer-specific survival (CSS).The best cutoff value of NLR was calculated by receiver operating characteristic (ROC) curve.The prognostic analysis of NLR on prostate cancer patients treated with MAB was estimated using Cox proportional hazards models and Kaplan-Meier analysis.Results The ideal cutoff value of the pretreatment NLR was 2.29 (95％ CI 0.603-0.737,P ＜0.001) determined by the ROC curve according to the survived and deceased cases at the end point of CSS,by which the 249 patients was divided into the high NLR group of 119 patients (47.8％) and the low NLR group of 130 patients (52.2％).High NLR was significantly associated with high Gleason score (P =0.019),higher clinical T stage (P =0.001),N stage (P ＜ 0.001),M stage (P ＜ 0.001) and more neutrophil count (P ＜ 0.001).The median follow-up time was 29 months (ranged 5 to 124).During this period,115 patients died,and the whole fatality rate was 46.2％.40 patients died in low NLR group (30.8％),while the figures for the high NLR group were 75 (63.0％).Kaplan-Meier analysis demonstrated that patients with NLR ≥ 2.29 had a poor outcome both in PFS (P ＜ 0.001) and CSS (P ＜ 0.001).The multivariate Cox analysis showed that NLR,Gleason score,clinical TNM stage and ECOG score were independent predictors for PFS and CSS.Conclusion Pretreatment NLR could be an independent prognostic biomarker for PFS and CSS in prostate cancer patients undergoing MAB.