OBJECTIVE - The aim of this study was to determine personal characteristics and preferences that affect decision making (decisional attributes) in patients with diabetes. In particular, we were interested in relating these attributes to the choice of using aspirin to reduce cardiovascular risk. RESEARCH DESIGN AND METHODS - We conducted a cross-sectional survey (70% response rate) of 206 diabetic patients (median age, 63 years; 42% women; 91% completed high school; median HbA1c 8%) attending a tertiary care diabetes clinic. Patients answered a 42-question survey exploring decisional attributes. Medical records provided the source of clinical information. We evaluated sociodemographic, clinical, and decisional predictors of aspirin use. We also conducted a multivariable analysis with aspirin use as a dependent variable. RESULTS - Sixty-seven percent of patients surveyed used aspirin. Patients using aspirin were at higher risk of cardiovascular disease (odds ratio 1.4, 95% CI 1.0-2.1), knew more about the benefits of aspirin (1.9, 1.4-2.6) and less about the risks of aspirin (1.4, 1.2-1.8), and were more certain about using aspirin (0.5, 0.3-0.8) than patients not using aspirin. Patients using aspirin placed a higher value on preventing cardiovascular events than on avoiding the side effects of aspirin. Patients perceived that their diabetes provider and the American Diabetes Association had greater influence on their decision to use aspirin than family members or other patients with diabetes. CONCLUSIONS - The decisional attributes of patients with diabetes are associated with aspirin use. Decisional attributes may be the target of research and interventions to reduce underutilization to levels consistent with patient preferences.