PURPOSE: To determine whether postsecondary research experiences (in college, medical school, and residency) and other variables mediate racial/ethnic disparities in U.S. medical school graduates' full-time faculty appointments in academic medicine. METHOD: Individualized, deidentified records for 1994-2000U.S. medical school matriculants who graduated with MDs before 2005, completed graduate medical education before 2009, and had data for all variables were examined for potential mediators of racial/ethnic disparities in full-time faculty appointments using the SAS macro "MEDIATE" for estimation and statistical inference. Controlling for gender, parents' occupation, and graduation year, the authors estimatedthe effects of potential mediators in separate models comparing Asian/Pacific Islander (PI) versus underrepresented minority (URM; including African American, Hispanic, and Native American/Alaska Native) graduates and white versus URM graduates. RESULTS: Of 82,758 eligible graduates, 62,749 (75.8%) had complete data; of these, 11,234 (17.9%) had full-time faculty appointments, including 18.4% (7,848/42,733) of white, 18.8% (2,125/11,297) of Asian/PI, and 14.5% (1,261/8,719) of URM graduates. Proportion of total race/ethnicity effect on full-time faculty appointment explained by all mediators was 66.0% (95% CI, 44.7%-87.4%) in a model comparing Asians/PIs with URMs and 64.8% (95% CI, 52.2%-77.4%) in one comparing whites with URMs. Participation in postsecondary research activities, authorship during medical school, academic achievement, and faculty career intentions at graduation were among the significant mediators explaining the effect of race/ethnicityonfull-time faculty appointment. CONCLUSIONS: Postsecondary research experiences for URM students are among the mediators of racial/ethnic disparities in full-time faculty appointments and, therefore, may increase academic medicine faculty diversity.