Three studies investigated the role of ruminative tendencies in mediating the effects of multidimensional perfectionism (Hewitt & Flett, 1991) on psychological distress. Study 1 (Sample 1, N = 279; Sample 2, N = 224) and Study 2 (N = 205) found evidence, cross-sectionally and prospectively, that brooding ruminative response style either fully or partially mediated the effects of socially prescribed and self-oriented perfectionism on psychological distress, depression and hopelessness levels. In addition, Study 3 (N = 163) confirmed these mediation effects for socially prescribed perfectionism in relation to depression and hopelessness, 2 months later, after initial levels of distress were controlled. Overall, these findings provide evidence that brooding ruminative response style is an important mechanism that can explain, in part, the relationship between perfectionism and distress. Copyright © 2006 John Wiley & Sons, Ltd.