Because various criteria are used to define metabolic syndrome (MetS), this study examines the most relevant definition for patients with benign prostatic enlargement (BPE). Most studies regarding the link between MetS and BPE/lower urinary tract symptoms (LUTS) have used the National Cholesterol Education Program Adult Treatment Panel III criteria for diagnosis, while a few have used criteria from the International Diabetes Federation and/or American Heart Association. Patients with LUTS due to BPE are classified as having MetS or not by the aforementioned three definitions. Prostate volume, International Prostate Symptom Score, storage and voiding subscores, maximum urinary flow rate, and the postvoid urine of patients with and without MetS were compared separately in the three different groups. Surgical and medical treatment prevalence was also compared between three groups. No matter which definition was used, the International Prostate Symptom Score, the storage and voiding symptom scores, prostate volume, prostate-specific antigen, and postvoid urine were significantly higher in the patients with MetS. The maximum urinary flow rate was similar between patients with and without MetS, according to all three different definitions. There was no significant difference in the aforementioned parameter between patients with MetS diagnosed with the three different definitions. Irrespective of which definition was used, the surgical treatment rate was not significantly different in patients diagnosed with than without MetS, or between the patients with MetS diagnosed with the three different definitions. The authors suggest that it does not matter which of the aforementioned three definitions is used during the evaluation of MetS in men with BPE/LUTS.