Spinal and bulbar muscular atrophy (SBMA) is a progressive hereditary neuromuscular disease caused by the testosterone-dependent accumulation of pathogenic polyglutamine-expanded androgen receptor protein. A 41-year-old man with SBMA received the androgen deprivation agent leuprorelin acetate for 7 years in clinical trials and underwent castration following the trial. Suppression of testosterone levels for 14 years resulted in a slower disease progression, as measured prospectively with quantitative measurements, than the historical control data reported in previous studies. This suggests that long-term androgen deprivation delays disease progression in SBMA.