Background: Serum cholesterol is one of the most important modifiable risk factors for coronary artery disease. There are conflicting data on racial and ethnic variation in the treatment of high cholesterol. Methods: We analyzed data from the Third National Health and Nutrition Examination Survey, a nationally representative cross-sectional survey conducted between 1988 and 1994. Participants included 7679 white, 4467 African American, and 4113 Mexican American adults older than 25 years who completed the household adult questionnaire. The adjusted odds of serum cholesterol screening and of taking a prescription medication to lower serum cholesterol among African Americans and Mexican Americans were compared with those of whites, controlling for differences in age, sex, income, educational level, insurance status, comorbid illness, and having a regular source of health care. Results: African Americans and Mexican Americans were significantly less likely than whites to report ever having had their blood cholesterol checked (odds ratio, 0.7 for both; P<.001). Among individuals with high cholesterol who were told to take a medication, African Americans (P<.001) and Mexican Americans (P = .05) were less likely than whites to be taking a cholesterol-lowering agent (odds ratios, 0.3 and 0.5, respectively). Individuals who reported being told they had high cholesterol had significantly higher serum cholesterol measurements (from the laboratory examination) than those who reported being told their cholesterol was not high (234 vs 198 mg/dL [6.05 vs 5.12 mmol/L]; P<.001). Conclusions: African Americans and Mexican Americans were less likely to report serum cholesterol screening than whites. Even when identified as having high cholesterol that required medication, African Americans and Mexican Americans were less likely than whites to be taking cholesterol-lowering agents.