A model of daily stress and metabolic control in Type I diabetes was tested in which stress has dual effects upon glycemic level: (a) direct, through psychophysiological mechanisms, and (b) mediated, through regimen adherence. Learned resourcefulness was postulated to moderate both effects. Two approaches to measuring daily stress were also compared: stress mean and variability. Daily stress and adherence were measured in 62 adult diabetics on six occasions over 2 months, after which glycosylated hemoglobin levels were obtained. Stress had a direct association with metabolic control that was not mediated by adherence. Although learned resourcefulness failed to moderate this relationship, it did relate directly to metabolic control, in the unexpected direction. The variables combined to explain 37% of the variance in metabolic control. The utility of the intraindividual approach to daily stress measurement was supported.