The 1997 CareData survey of members of Medicare risk health maintenance organizations (HMOs) measured the degree of satisfaction of Medicare managed care members with emphasis on pharmacy-related issues and specific disease treatment perceptions. The survey was a 12-page, self-administered questionnaire assessing more than 150 issues; it was distributed to 23,140 known enrollees of Medicare risk HMOs by their former employers between May and July 1997. A total of 12,265 Medicare beneficiaries enrolled in more than 70 major health plans in 23 US geographic markets completed and returned their questionnaires (response rate, 53%). The pharmacy benefit was cited by 75% of the respondents as the reason for joining their plan; 81% of the respondents reported being highly satisfied with the pharmacy benefit overall, with regional variations from a low of 60% to a high of 82%. The issues driving enrollees' satisfaction after being in their plan for a minimum of 6 months and a mean length of slightly more than 3 years were: satisfaction with customer service and plan administration (11.6% explained variance); the plan's concern for the member's well-being (10.6%); the belief that the care improved the member's health and well-being (9.2%); satisfaction with choice of specialists (5.3%); satisfaction with the pharmacy plan (5.1%); and satisfaction with the primary care physician (4.8%). Significant variations were seen among regions, plans, and the self-reported health status of the respondents.