Objective To assess whether an intervention to help patients prioritize goals for their visit would improve patient-provider communication and clinical outcomes. Design Randomized controlled pilot study. Setting Primary care clinic. Participants There were 120 adult hypertensive patients enrolled. Intervention Patients were randomized to receive either usual care or a previsit patient activation card developed through a series of focus groups that prompted patients to articulate their needs and set priorities for their clinic visit. Encounters were audiorecorded, transcribed, and assessed using duplicate ratings of patient activation and decision making. Main outcome measures The primary outcome was change in medication adherence as measured by pill count at 4 and 12 weeks after the initial visit. Secondary outcomes evaluated patient-provider interaction quality (patient satisfaction, patient activation, shared decision making, patient trust, and physicians' perceived difficulty of the encounter), functional status, and blood pressure control. Results Of the 120 enrolled patients, 106 completed the baseline visit (mean age of 66 years, 53% women, 57% Black, 36% White). Participants had multiple comorbidities (median number of medications=8). During the visit, there was greater patient activation in the intervention arm than in the control arm (4.4 vs 3.8, P=.047; ratings were based on a scale from 1 to 10). However, after the visit there were no differences in medication adherence (4 weeks: 45.8% vs 49.5%; 12 weeks: 49.4% vs 51.1%), blood pressure control (4 weeks: 133/78 mm Hg vs 131/77 mm Hg; 12 weeks: 129/77 mm Hg vs 129/76 mm Hg), or encounter satisfaction (78.6% vs 73.8% fully satisfied; P=.63). There were also no differences in shared decision making, patients' trust, or perceived difficulty of the encounter. Conclusion A single previsit tool designed to prompt patients to set a prioritized agenda improved patient activation during the visit, but did not affect the quality of the interaction or postvisit patient-centred outcomes.