Studies on the pharmacokinetics of the antibiotic garenoxacin (GRNX) in patients with renal insufficiency are lacking. In this study, we attempted to ascertain the appropriate dose of GRNX in patients undergoing maintenance hemodialysis (MH) based on pharmacokinetic parameters and clinical outcomes. Six male patients with infections who were undergoing MH received 200 mg GRNX once daily. Blood samples were taken before and at 1, 2, 4, 6, 12, and 24 hours after GRNX administration. Plasma GRNX concentrations were measured using high-performance liquid chromatography. The mean maximum plasma concentration (Cmax ) was 3.00 ± 1.12 µg/mL, time to maximum plasma concentration (Tmax ) was 3.0 ± 2.0 hours, and area under the curve for 24 hours (AUC0-24 ) was 40.7 ± 16.7 µg·h/mL. The half-life (T1/2 ) of GRNX could not be calculated because plasma concentrations remained high 24 hours after administration. Cmax was strongly associated with the GRNX dose per kilogram body weight (r = 0.85, P = 0.03). Clinically, fever resolved within 3 days of GRNX administration and C-reactive protein levels returned to normal 14 days after administration. One patient experienced temporary increases in serum transaminase levels. MH patients receiving 200 mg GRNX once daily for infection showed a reduced Cmax but similar AUC0-24 compared with healthy individuals. While this study evaluated the effect of GRNX treatment, further research is needed to assess the accumulation of GRNX and the impact of continuous administration on its pharmacokinetics, as well as to prevent the development of resistant mutants.