The purpose of this study was to test a structural equation model of cardiac risk factor behavior among 101 participants in a cardiac rehabilitation program. The structural model contained physiologic, health-related, and psychosocial variables that were based on theories of cardiac physiology, social cognition, and attributions. The hypothesized model was analyzed via LISREL VI (Joreskog & Sorbom, 1986) and proposed causal connections among the following latent variables: Cardiac Status to Attributions, Cardiac Risk Factor Self-Efficacy, and Cardiac Risk Factor Behavior; Attributions to Cardiac Risk Factor Behavior; and paths of mutual influence between Cardiac Risk Factor Self-Efficacy and Cardiac Risk Factor Behavior.^ Data were collected from all subjects in a phase II cardiac rehabilitation program in a northeast city from February 28, 1990 to November 30, 1990. Of the 110 subjects in the target population, 101 participants comprised the study sample and 9 participants comprised the attrition sample.^ Sixteen observed indicators were measured to estimate the causal parameters linking four latent variables. After measurement model respecification, the structural equation model of cardiac risk factor behavior demonstrated a good fit ($\chi$2(37, N = 101) = 41.83, p =.269) and supported the hypothesized hierarchical, direct causal effects from: Cardiac Status to Cardiac Risk Factor Behavior, Attributions to Cardiac Risk Factor Self-Efficacy, and Cardiac Risk Factor Self-Efficacy to Cardiac Risk Factor Behavior. No direct effects were found from Cardiac Status to Attributions or to Cardiac Risk Factor Self-Efficacy, nor from Cardiac Risk Factor Behavior to Cardiac Risk Factor Self-Efficacy.^ These results lend validity to the theoretical underpinnings that link both physiologic and cognitive variables to cardiac risk factor behavior in this population. They specifically support the roles of self-efficacy as a cognitive mediator of action and attributions as a source of efficacy information, and offer an empirical basis for developing and testing interventions in cardiac rehabilitation programs.