Background. Effective chronic disease self-management among older adults is crucial for improved clinical outcomes. We assessed the relative importance of two dimensions of physician communication – provision of information (PCOM) and participatory decision-making (PDM) – for older patients' diabetes self-management and glycemic control. Methods. We conducted a national cross-sectional survey among 1588 older community-dwelling adults with diabetes (response rate: 81%). Independent associations were examined between patients' ratings of their physician's PCOM and PDM with patients' reported diabetes self-management (medication adherence, diet, exercise, blood glucose monitoring, and foot care), adjusting for patient sociodemographics, illness severity, and comorbidities. Among respondents for whom hemoglobin A1c (HbA1c) values were available (n = 1233), the relationship was assessed between patient self-management and HbA1c values. Results. In separate multivariate regressions, PCOM and PDM were each associated with overall diabetes self-management (p < .001) and with all self-management domains (p < .001 in all models), with the exception of PDM not being associated with medication adherence. In models with both PCOM and PDM, PCOM alone predicted medication adherence (p = .001) and foot care (p = .002). PDM alone was associated with exercise and blood glucose monitoring (both p < .001) and was a stronger independent predictor than PCOM of diet. Better patient ratings of their diabetes self-management were associated with lower HbA1c values (B = -.10, p = .005). Conclusion. Among these older adults, both their diabetes providers' provision of information and efforts to actively involve them in treatment decision-making were associated with better overall diabetes self-management. Involving older patients in setting chronic disease goals and decision-making, however, appears to be especially important for self-care areas that demand more behaviorally complex lifestyle adjustments such as exercise, diet, and blood glucose monitoring. Copyright 2007 by The Gerontological Society of America.