AbstractThe ultrasonic fatigue testing method was standardized in the Japan Welding Engineering Society. Scope of this standard is limited for metallic materials tested at room temperature. This standard applies not only to axial loading by longitudinal oscillation but also to torsional loading by torsional oscillation. The stipulated specimens are an hourglass‐shaped type, while other types of specimens are also acceptable. Explanation attached to this standard discloses data and theories behind each requirement. In particular, massive data are disclosed for a frequency effect with comparisons of the data between ultrasonic and conventional fatigue testings. The data are disclosed on low‐ and high‐strength steels, austenitic stainless steels, cast irons, titanium alloys, and aluminum alloys. These data suggest that the ultrasonic fatigue testing is well suited to high‐strength materials but not low‐strength materials. In addition to the introduction of the standard, studies using the ultrasonic fatigue testing are exampled in this paper.