The distribution of C-reactive protein (CRP) levels was compared among 24,455 white, 475 black, 357 Asian, and 254 Hispanic women, all of whom are participants in the Women's Health Study. Median CRP levels were significantly higher among black women (2.96 mg/L, interquartile range [IQR] 1.19 to 5.86) than among their white (2.02 mg/L, IQR 0.81 to 4.37), Hispanic (2.06 mg/L, IQR 0.88 to 4.88), and Asian (1.12 mg/L, IQR 0.48 to 2.25) counterparts. As expected, women taking hormone replacement therapy had higher baseline CRP levels than women not taking hormone replacement therapy. No differences in low-density lipoprotein cholesterol or total cholesterol levels were observed between ethnic groups. In multivariate regression models, body mass index was a significant (p <0.001) predictor of elevated CRP concentrations among all race/ethnic groups, and control for body mass index substantially attenuated the differences noted in CRP levels across race/ethnic groups, particularly among black women. Control for all measured modifiable risk factors for cardiovascular disease did not entirely explain CRP differences. Among these women, the distribution of CRP levels varied significantly between the various race/ethnic groups.