The aims of this study were to (1) determine the association between ethnicity and thoracic aortic calcium (TAC) and abdominal aortic calcium (AAC) and (2) investigate associations between cardiovascular disease (CVD) risk factors and TAC and AAC. Participants were 1,957 men and women enrolled in the Multi-Ethnic Study of Atherosclerosis who had computed tomographic scans of the chest and abdomen. These scans were obtained at the same clinic visit and calcium scores were computed using the Agatston method. Regression analyses were conducted using relative risk regression. Mean age was 65 years and 50% were women. Forty percent were white, 26% Hispanic, 21% African-American, and 13% Chinese. Whites had the highest prevalence of AAC (80%), which was significantly higher than Hispanics (68%, p <0.001), African-Americans (63%, p <0.001), and Chinese (74%, p = 0.029). Similarly, whites had the highest prevalence of TAC (42%), which was significantly higher than in Hispanics (30%, p <0.01) and African-Americans (27%, p <0.001) but was not significantly different from that in Chinese (38%). Compared to whites and after adjustment for age, gender, body mass index, hypertension, diabetes, dyslipidemia, smoking, and family history of CVD, Hispanics and African-Americans, but not Chinese-Americans, had a significantly lower risk for the presence of any AAC or any TAC. In these models, diabetes, smoking, and dyslipidemia had stronger associations with AAC, whereas hypertension was stronger for TAC. In conclusion, compared to whites, African-Americans and Hispanics, but not Chinese, have evidence of less atherosclerosis in the thoracic and abdominal aortas, which does not appear to be accounted for by traditional CVD risk factors.