OBJECTIVE: To investigate whether providing information about normal findings before a diagnostic test improves patients' reassurance and reduces anxiety about symptoms. DESIGN: Randomised controlled trial. SETTING: Outpatient cardiology clinic. PARTICIPANTS: 92 patients with chest pain referred for a diagnostic exercise stress test. INTERVENTION: Before undergoing testing patients were randomised to receive standard information (n=28; control group), a pamphlet explaining the function of the test and the meaning of normal test results (n=30; pamphlet group), or the pamphlet and a brief discussion about the meaning of normal test results (n=34; discussion group). MAIN OUTCOME MEASURES: The primary outcome was patients' reported reassurance on a 5 item scale immediately after the test and at one month. Secondary outcomes were the proportion of patients still with chest pain and still taking cardiac drugs at one month. RESULTS: The mean levels of reassurance after testing and feedback from the doctor were significantly higher in the discussion group (42.0, 95% confidence interval 39.7 to 44.2) than in the pamphlet (39.2, 36.1 to 42.3) and control groups (35.8, 31.6 to 39.9). This difference was maintained at one month. The proportion of patients still reporting chest pain at one month decreased significantly in the discussion group (to 17%) and pamphlet group (to 28%) but not in the control group (to 36%). A trend was for fewer patients in the discussion group to be taking cardiac drugs at one month. CONCLUSION: Providing patients with information about normal test results before testing can improve rates of reassurance and reduce the likelihood of future reports of chest pain. TRIAL REGISTRATION: Current Controlled Trials ISRCTN87589121 [controlled-trials.com].