The effect of social roles (partner, parent, worker) on mental health may depend on the total number or the quality of the individual occupied social roles. With longitudinal data from the Netherlands Mental Health Survey and Incidence Study (NEMESIS), the effect of the number and quality of occupied social roles on mental health over three years was examined among 2471 men and women aged 25-55 years without mental disorders at baseline. Mental health was assessed using 3-year change in the SF-36 mental health scale as well as using the 3-year incidence of anxiety and depressive disorders defined by DSM-III criteria. The quality of social roles was assessed by the GQSB (Groningen Questionnaire Social Behavior). The number of social roles had no significant effect on the risk of developing depressive and anxiety disorders, but particularly the partner-role had a significant positive effect on mental health (β of mental health = 1.19, p = 0.01; HR of incident disorders = 0.75, 95% CI:0.51-1.00, p = 0.05). A good quality of each of the three social roles was associated with higher levels of mental health and lower risks of incident disorders over 3 years. More than the number of social roles, knowledge about social role quality might provide opportunities for prevention of depressive and anxiety disorders. © 2008 Elsevier B.V. All rights reserved.