MentorNet (www.MentorNet.net), a nonprofit organization founded in 1997 as an online network for women in engineering and science, developed a large-scale one-on-one mentoring program, which has served tens of thousands of participants over the years of its operation. As participation grew, the increasing numbers of participants who selfidentified as people of color eventually provided a large enough dataset to analyze the program by race/ethnicity. This study seeks to shed light on the experiences of women of color, as programs designed to benefit the majority population may not serve all participants equally well. We also know that the group of professionals volunteering as mentors was not as diverse as the group of students seeking mentoring.Program evaluations based on responses to end-of-relationship surveys, taken together with data collected when participants first applied for the program, reveal that many students of color are particularly interested in discussing issues of race with a mentor. Even in cases where students initially expressed a preference to be matched with a mentor of the same race, however, their satisfaction at the end of a mentoring relationship was no less if they had been matched with a person of a different race. Students of color were more likely than White students to attribute their retention in college and increased motivation to succeed in their chosen fields to having an external mentor. Professionals participating as mentors who were people of color reported increased self-confidence from the experience, more so than did White mentors.