Background It is still controversial whether the serum inhibin B level is a superior predictor of the presence of sperm in testicular sperm extraction (TESE) in azoospermic men compared with serum follicle-stimulating hormone (FSH).In this study,we evaluated the diagnostic accuracy of serum inhibin B levels as a predictor of the outcome of TESE in Chinese non-obstructive azoospermic men and compared it with the traditional marker serum FSH and testicular volumes.Methods Basal values of serum hormone levels,testicular volumes and histological evaluation of 305 Chinese non-obstructive azoospermic men were analyzed.The level of inhibin B was measured using a three-step enzyme-linked immunoassay before sperm extraction,and the diagnostic accuracy of prediction of the outcome of TESE was compared for different markers by the receiver operating characteristics (ROC) curve analysis.Results Testicular sperm was successfully retrieved in 137 of 305 patients (44.9％).The serum level of inhibin B,the FSH and the testicular volume were significantly different between the successful TESE group and the unsuccessful group.According to the ROC curve analysis,for inhibin B,the cut-off value for discriminating between successful and failed TESE was 28.39 pg/ml (sensitivity 83.5％,specificity 79.1％).For FSH,the best cut-off value for discriminating was 11.05 pg/ml (sensitivity 83.5％,specificity 74.5％).The area under the ROC curve of serum inhibin B was similar to that of FSH.Combining the serum inhibin B with FSH levels did not improve the predictive value for successful TESE.Conclusions Serum inhibin B and FSH levels are correlated with spermatogenesis.However,inhibin B is not superior to FSH in predicting the presence of sperm in TESE.And the combination of them does not improve the diagnostic accuracy on TESE outcome.