Degradation and recovery of damping capacity in a Cu-65%Mn alloy have been studied. When the alloy was isothermally aged at $400^{circ}C$, the highest damping capacity was observed after aging for 4 hours. In case when the alloy aged at $400^{circ}C$ for 4 hours was maintained at $100^{circ}C$, the damping capacity gradually decreased with time. The microstructural observations showed that the formation of subdomains and ${alpha}$-Mn precipitates are responsible for the degradation of damping capacity. When the degraded specimen was reheated at $250^{circ}C$ for 30 minutes, the damping capacity was recovered considerably owing to the redistribution of impurity atoms, the extinction of subdomains and the release of damping sources from ${alpha}$-Mn precipitates during the repeated transformation, fcc${leftrightarrow}$fct.