Members of the American Society of Training and Development (ASTD) served as subject matter experts in order to develop and validate the content of an instrument to measure organizational support for training. More specifically, in the two step process utilized in the present research, nine members of a single urban chapter of the ASTD participated in a focus group to generate an initial instrument item list of 79 items. In the second stage of the study, 5,012 national members of the ASTD rated the relative importance of each of the original items in terms of each item's ability to measure organizational support for training. The resulting analysis provided the basis for the 25-item Organizational Training Support Inventory (OTSI).