This study examined constructs drawn from social-cognitive theory (A. Bandura, 1986) and self-determination theory (E. L. Deci & R. M. Ryan, 1985, 1991) in relation to dietary self-care and life satisfaction among 638 individuals with diabetes. A motivational model of diabetes dietary self-care was proposed, which postulates direct links between self-efficacy/autonomous self-regulation, and adherence/ life satisfaction. Structural equation modeling showed that both self-efficacy and autonomous self-regulation were associated with adherence (betas = .54 and .21, respectively) and with life satisfaction (betas = .15 and .34, respectively). Constraint analyses confirmed that self-efficacy was significantly more associated with adherence, whereas autonomous self-regulation was significantly more associated with life satisfaction. According to the model, interventions for dietary self-care and life satisfaction should focus on increasing self-efficacy and autonomous self-regulation.