This study examined four propositions by which social support may impact the physical and mental well-being of the bereaved: (1) social support has a direct effect on health; (2) social support reduces stress which, in turn, affects health; (3) social support stimulates the development of coping strategies and promotes mastery, thereby affecting health; and (4) social support promotes health protective behaviors which, in turn, impact on health. Data to test the proposed model were collected through semi-structured interviews and standardized questionnaires with 490 widows and widowers at 6 weeks (T1), 6 months (T2), 12 months (T3), 18 months (T4), and 24 months (T5) following the loss of the spouse. A linear structural equation approach using the statistical program LISREL was employed in the analysis of data. A model was estimated with an adequate fit for T1, T2, and T3, but not for T4 or T5. There was no evidence for a direct effect of social support on the well-being of the bereaved. In examining the indirect effects of social support, parameter estimates were consistent with the premise that social support enhances coping behaviors which, in turn foster well-being (as evidenced by diminished illness symptomatology). Perceived stress also had a direct positive effect on illness symptomatology. (Six figures and 25 references are included.) (Author)