<p>Background: Remarkably, the current study is one of the first to deploy galectin-1 (Gal-1) in determining the degree of impairment of spermatogenesis among cases with non-obstructive azoospermia (NOA) as well as utilizing it as a biomarker to predict the rate of sperm retrieval in these patients. The purpose of the study was to evaluate the seminal plasma and serum levels of Gal-1 in NOA patients as well as their correlations with Johnsen&rsquo;s tubular biopsy scoring (JTBS).<br /> Methods: The current case control study included totally 48 patients with NOA whose ages ranged from 24 to 46 years old and 50 age matched healthy controls. Gal-1 levels were measured in both seminal plasma and serum of all subjects by the enzyme-linked immunosorbent assay (ELISA).<br /> Results: A significant negative correlation between seminal plasma levels of Gal-1 and JTBS was detected (r=-0.281, p=0.048) in the NOA cases. Interestingly, the receiver operating characteristic (ROC) curve had demonstrated that the cutoff value of seminal plasma levels of Gal-1 in determining azoospermia was &gt;0.735 ng/ml and the area under the curve (AUC) was 0.858. The sensitivity, specificity, positive predictive, and negative predictive values for seminal plasma levels of Gal-1 were 76, 92, 90.5, and 79.3, respectively. In addition, sensitivity, specificity, positive predictive, and negative predictive values for serum levels of Gal-1 were 38, 66, 52.8, and 51.6, respectively.<br /> Conclusion: Seminal plasma levels of Gal-1 are higher in NOA men versus healthy controls. Interestingly, negative correlation of seminal plasma levels of Gal-1 with JTBS was determined. Thus, it can be used as a good predictor for NOA cases.</p>