OBJECTIVE: To test the hypothesis that Alaska Natives have fewer atherosclerotic lesions in the coronary arteries and aorta than nonnative Alaska residents. DESIGN: Systematic standardized collection and evaluation of coronary arteries and aortas collected at autopsy. SETTING: Forensic autopsy service in Alaska. SUBJECTS: One hundred thirty Alaska Natives and 115 Alaska nonnatives who underwent forensic autopsy between February 1989 and December 1993. INTERVENTION: None. MAIN OUTCOME MEASURES: Prevalence and extent of atherosclerotic lesions in the aortas and coronary arteries in both populations studied. RESULTS: Alaska Natives had significantly lower prevalence and extent of raised atherosclerotic lesions in the abdominal aorta and coronary arteries than nonnative Alaska residents. CONCLUSIONS: Differences in coronary heart disease mortality between Alaska Natives and nonnatives are, at least in part, the result of fewer atherosclerotic lesions in Alaska Natives.