Although the impact of cocaine on clinical cardiovascular events has been identified and studied, the effects of cocaine use on subclinical coronary artery disease (CAD) has not yet been thoroughly investigated. In the past 12 years, we have been following up approximately 1,000 African American (AA) cocaine users in Baltimore to investigate cardiovascular complications of its use in people with and without HIV infection. We have found that (1) long-term cocaine use is associated with the presence of coronary noncalcified plaque, (2) long-term cocaine use is associated with endothelial dysfunction markers, and (3) atherosclerotic plaque can be reversed with statins medication. Although noncalcified plaques tend to be more vulnerable to rupture, they are early lesions and could be reversed with statin medication. Because of newly developed software that measures changes in coronary noncalcified plaque volume and the availability of low radiation dose modality with the second-generation Siemens CT scanner, coronary CT angiography (CTA) can now be used to quantify changes in coronary noncalcified plaque volume. Since a large proportion of cocaine users are infected with HIV and/or hepatitis C, which may put them at increased risk of statin-induced hepatotoxicity, a nonpharmaceutical intervention for cocaine-induced CAD is urgently needed for this population. Responding to this RFA, we propose to conduct a 3-year longitudinal study to determine whether reductions in cocaine use lead to reductions in coronary noncalcified plaque volume in chronic cocaine users. The reductions in cocaine use will be achieved with the use of well-established voucher-based incentives. A total of 140 AA chronic cocaine users with noncalcified plaques and low Framingham scores will be recruited into this investigation. Each participant will participate in a 12-month voucher-based incentives program to promote cocaine abstinence or reduce cocaine use and will be followed intensively during this time for collection of drug use data. Coronary CTA with contrast will be performed 3 times during the study: baseline, 6-month follow-up, and 12-month follow-up. We will correlate the changes in cocaine use with changes in volume of coronary noncalcified plaque. The specific aims of this proposed study are as follows: (1) To evaluate the effects of voucher-based incentives therapy on coronary noncalcified plaque volume in chronic cocaine users, (2) To use coronary CT angiography to examine changes in coronary noncalcified volume associated with changes in the levels of cocaine use, and (3) To evaluate changes in biomarkers of endothelial function associated with changes in the levels of cocaine use. If reductions in cocaine use lead to a favorable outcome, this study could be translated into well-designed clinical trials to confirm and validate our findings. The proposed study will be the first to focus on secondary prevention of CAD with the use of voucher-based interventions in chronic cocaine users.