Abstract Background Coronary heart disease (CHD) is the leading cause of death in the United States. Previous research examining physicians ability to estimate cardiovascular risk has shown that physicians' generally overestimate the absolute risk of CHD events. This question has, however, only studied risk prediction for a limited number of patient care scenarios. The aim of this study is to measure the ability of physicians to estimate the risk of CHD events in patients with no previous history of coronary heart disease. Methods Twelve primary prevention scenarios with a 5-year risk of CHD events were developed. This questionnaire was surveyed at 3 university teaching hospitals where the participants were a convenience sample of internal medicine residents and fellows or attending physicians in general internal medicine or cardiology. For each scenario, physicians were asked to estimate the baseline 5-year risk of a coronary heart disease event and the revised risk if the patient were to receive lipid-lowering drug therapy. Estimates of the baseline 5-year risk were compared with values calculated from Framingham risk equations. Inaccurate responses were defined as those with a ratio of estimated to actual risk of more than 1.5 or less than 0.67. Physicians' estimates of the relative risk reduction with therapy were considered to be accurate if they were between 25% and 40%. Results 79 physicians (53 residents, 8 fellows, 18 attending physicians) completed the survey. Only 24% of physicians' risk estimates were accurate. In most cases, physicians overestimated the absolute risk of cardiovascular events without therapy (proportion overestimating ranged from 32–92% for the 12 individual scenarios). Physicians made larger errors in patient scenarios involving patients with high total or LDL cholesterol levels. Physicians' estimates of the relative risk reduction from treatment were more accurate: 43% of estimates were between 25 and 40%. Over 85% of physicians recommended treatment in 10 of 12 scenarios. Conclusions Physicians overestimate the absolute risk of CHD events and the potential absolute benefit of drug therapy.