Carbon fiber reinforced plastics (CFRP) have a widespread engineering applications due to their superior properties however, their machining cost is high. Cost effective machining processes are needed for CFRP. Rotary ultrasonic machining (RUM) is a nontraditional machining process for CFRP. RUM utilizes a rotating tool with ultrasonic vibration along the axial direction. Drilling is the most commonly needed machining practice for CFRP. In this study, a drilling test was conducted to investigate input variables, i.e. ultrasonic power, tool rotation speed, and feedrate for RUM of CFRP. A two-level three-factor full factorial design was used for experiment. The design of experiment approach was used to obtain main effects, two-factor interactions, and three-factor interactions on cutting force, torque, and surface roughness.