PURPOSE. We assessed patients' preferred role and perceived level of involvement in medical decision making and tested the effects of patients' age and role preference on perceived involvement in medical decision making. METHODS. We conducted a telephone survey of 90 adults being treated for heart failure by a Veterans Affairs primary care provider or cardiologist. Patients' preferred role in treatment decisions was assessed using the Control Preferences Scale, a single-item Likert type scale on which patients indicate the degree of control they prefer to have in medical decision making, with high scores indicating a preference to assume a more passive role. Perceptions about their involvement in decision making during the most recent clinic visit was measured using a summated subscale of the Perceived Involvement in Care Scale (PICS) yielding a single numeric score. Descriptive, correlational, and linear regression analyses were conducted. RESULTS. Most patients were elderly (mean = 70.1 years), male (94.4%), white (85.6%), and had NYHA Class II disease (55.6%). Forty-three patients (47.8%) preferred a passive role in decision making, 19 (21.1%) an active role, and 28 (31.1%) a collaborative role. Most patients believed that their decision-making involvement was relatively passive, as indicated by a mean score of 0.96 (ranged from 0-4) on the PICS decision making subscale. Older age was associated with passive role preference (r = 0.266; P<.05) and less perceived involvement in decision making (r = –0.279; P<.01). In addition, less perceived involvement in decision making during the last clinic visit was associated with a preference for a more passive decision-making role (r = –0.362; P<.01). Linear regression analyses indicated that when age and patients' role preferences were regressed on patients' perceived decision-making involvement, age was no longer significantly associated with involvement (β = –0.197; P = .056), but that control preferences continued to exhibit an independent effect on perceived involvement in medical decision making (β = –.310; P = .003). CONCLUSIONS. Multivariate analyses suggested the independent effect of patients' role preferences on perceptions of involvement during the most recent clinic visit may be stronger than those of patients' age. Results suggest that heart failure patients' preferences for a more passive role in decision making may be a stronger independent predictor of patients' perceived involvement in decision making than patients' age.