Wire electrical discharge turning (WEDT) is suitable for machining of precise cylindrical forms on hard and difficult-to-cut materials. In WEDT electrical discharge takes place between the traveling wire and the rotating workpiece to be machined. However, in many cases the machining efficiency of WEDT is considered to be rather low. One of the methods to enlarge the application envelope of WEDT and to improve its machining performance on difficult-to-machine materials is introduction of ultrasonic vibration to the wire electrode. An investigation has been made to combine ultrasonic vibration and wire electrical discharge turning. Design of a submerged, precise, flexible and corrosion-resistant rotary spindle is introduced. The spindle was mounted on a five-axis wire EDM machine to rotate the workpiece in order to generate free form cylindrical geometries. An auxiliary device which produces ultrasonic vibration was installed between the two wire-guides. The ultrasonic system consists of an ultrasonic generator, a transducer and a wire holder. When the wire is being driven, the transducer together with the wire holder vibrate under the resonance condition. Material removal rate (MRR) indicates efficiency and cost-effectiveness of the process. Experimental results show that wire vibration induced by ultrasonic action has a significant effect on material removal rate. This study has been to evaluate the influence of four design factors: power, pulse off time, spindle rotational speed and ultrasonic vibration over material removal rate. This has been done by means of design of experiments (DOE) technique. Analysis of variance (ANOVA) was used to determine significant effective factors.