There is provided a method and system for acoustic signature health monitoring of an unmanned autonomous vehicle (UAV). The method positions an acoustic signature health monitoring system proximate to and off-board a UAV to be monitored for mechanical health of one or more sound producing structures. The method obtains and analyzes with the system a baseline acoustic signature for each of the sound producing structures, and transmits each baseline acoustic signature to a data processing system for processing. The method obtains and analyzes one or more subsequent acoustic signatures for each of the sound producing structures, and transmits the one or more subsequent acoustic signatures to the data processing system. The method compares the processed baseline acoustic signature with the one or more processed subsequent acoustic signatures for the sound producing structures, in order to detect any change in the processed baseline acoustic signature over time.