The effects of anode temperature on the performance of a 5-kW Hall-effect thruster are investigated. The performance characteristics of the P5 Hall-effect thruster are measured with and without active cooling of the anode. Thrust, ion current density, anode temperature, and cooling power are measured for discharge voltages between 100 and 500 V at xenon propellant flow rates of 4.97 and 10.0 mg/s. All experiments are performed in a 4 by 7 m stainless-steel vacuum chamber at pressures below 2.4 x 10 ―5 Torr corrected for xenon. At 100 V, 4.97 mg/s, cooling affects a 6.3% increase in anode efficiency and a 56% increase in thrust-to-power (T/P). At 100 V, 10.0 mg/s, cooling affects a 2.0% increase in anode efficiency and a 7.5% increase in T/P. For both propellant flow rates, the cooled anode efficiency unexpectedly decreases as the discharge voltage increases, which leads to a maximum anode efficiency loss of 5.0 and 9.1 % at 4.97 and 10.0 mg/s, respectively.