As in many universities, a number of departments at Southern Illinois University-Carbondale rely on GTAs to fulfill their educational mission. Yet, there is a major gap between the responsibilities we assign to GTAs and the investment we make in their proper training. The GTA training program described herein involves supplementing a university-wide GTA workshop with a discipline-specific seminar series aimed at improving teaching skills and broader professional practice-related skills. These improvements promote GTAs' confidence in the classroom and can be used as a foundation for programs such as the U.S. Department of Education's Graduate Assistance in Areas of National Need (GAANN) program, which require awardees to undertake supervised teaching appointments. The seminars also indirectly impact a department's ability to meet institutional or program-related goals. Postseminar survey data indicates that the pilot training program has been beneficial, and faculty are already witnessing the application of some of the material presented (e.g., GTAs establishing grading rubrics, outlining clear objectives in laboratory sections, and conducting more efficient literature searches for their research). This, in itself, is a good indication that the seminar series and the Guide for Teaching Assistants have positively impacted GTAs and the overseeing department. It is recommended that future seminars be offered at a college level to improve the cost-effectiveness of the program. At SIUC, this expanded effort is being supported by the SIUC Center for Graduate Teaching Excellence. Furthermore, it is recommended that the administering unit consider incentives or implementation of a GTA certification program to address attendance issues. © 2007 ASCE.