Michigan State University (MSU) is strongly committed to the idea that study abroad is deeply beneficial and important for undergraduate students. However there is a relative scarcity of systematically gathered qualitative and quantitative information that assesses the impact of study abroad. In the summer of 2000, MSU implemented a broad plan to design and put in place mechanisms for continuously assessing the impact of study abroad on students, on faculty, and on MSU as a whole. From the beginning, "assessment of the impact of study abroad" was broadly construed to focus on measuring the acquisition of knowledge, skills and attitudes that students need to live and work in the 21st century. The assessment project is expected to continue indefinitely and so far two phases have been completed. In this article, the authors report preliminary results of Phase I and II, which explore study abroad's impact on students. Seeking evidence that MSU students going abroad are achieving learning goals, the study uses a variety of instruments and methods, qualitative and quantitative. The authors discuss some of the project's findings from student surveys, faculty reports, and the MSU database in terms of the primary areas in which MSU intends study abroad to have an impact on students: intellectual growth (including both academic performance and language learning), personal growth, intercultural awareness, and professional development. (Contains 2 tables.)