Using welded-wire reinforcement (WWR) as an alternative to traditional mild steel reinforcing bars has many advantages. WWR has a higher yield strength and is produced under higher quality control standards. Its use also results in fewer labor costs associated with construction. However, many designers are reluctant to use WWR as an alternative to mild steel reinforcing bars due to the unavailability of fatigue design guidance in the American Association of State Highway and Transportation Officials�? AASHTO LRFD Bridge Design Specifications. This paper reports on a fatigue testing program of deformed, high-strength WWR. Based on the results of this testing program, a conservative stress range formula for WWR is presented. This same formula has been adopted for use in the 2007 Interim AASHTO LRFD Bridge Design Specifications. In addition, full monotonic axial tensile stress-strain relationships are presented.