The clinical practice manual for late-onset hypogonadism (LOH) was updated in 2022. This study analyzed the total and free testosterone levels of patients who visited our specialized hypogonadism outpatient clinic and examined the characteristics of patients eligible for androgen replacement therapy (TRT), using the 2007 guidelines and the new guidelines as references. Among a total of 770 patients that visited our clinic,11.9% (92/770) of the patients had total testosterone levels (＜250 ng/dl) that met the LOH diagnostic criteria of the new guidelines,and 39.2% (302/770) had free testosterone levels (＜7.5 pg/ml) that met the LOH diagnostic criteria. These patients represented 62.2% of the patients who underwent TRT,according to the 2007 guidelines. When patients who underwent TRT were divided into two groups depending on whether they met the diagnostic criteria in the new medical treatment guide,there was no significant difference in the subjective effectiveness rate of TRT and the improvement rate of Aging Males’Symptoms (AMS) score before and after TRT.