We investigated the influence of sarcopenia on treatment outcomes in elderly patients receiving medical therapy for lower urinary tract symptoms (LUTS). We included male patients with LUTS aged ≥ 75years who had not changed their medication for 1year. Current conditions were estimated using IPSS, overactive bladder symptoms score (OABSS), and screening tool for sarcopenia (SARC-F). We also evaluated prostatic volume (PV), serum testosterone level, grip strength, and nutrition status. SARC-F score of ≧4 was defined as sarcopenia. We included 59 patients in this study, including 16 patients (27.1%) with sarcopenia. The mean grip strength was significantly lower in the sarcopenia group than the non-sarcopenia group (25.5 vs. 30kg, p < 0.01). IPSS total score, voiding symptom score of IPSS, and IPSS-QOL were significantly higher in the sarcopenia group than the non-sarcopenia group. The non-sarcopenia group had significantly larger PV (40 vs. 20ml, p < 0.01) and higher testosterone levels (497.5 vs. 369ng/ml, p = 0.03) compared with the sarcopenia group, whereas the percentage of patients taking dutasteride tended to be higher in the non-sarcopenia group than the sarcopenia group (58.1% vs. 31.3%, p = 0.07). Moderate and severe LUTS (IPSS total ≥ 8) persisted in 34 patients (57.6%) after medical treatment. Multivariate analysis showed that only SARC-F was a significant factor affecting the IPSS total ≥ 8 despite medical treatment for 1year (OR 1.67, 95%CI: 1.13-2.46, p = 0.01). Sarcopenia defined by using SARC-F is a significant factor for unsatisfactory medical treatment of LUTS in elderly men aged ≥ 75years.