Purpose: Genetic screening can enable timely detection and treatment of hereditary hemochromatosis (HH). Little is known about patient acceptability of DNA testing as compared to conventional phenotypic testing. Methods: Within the HEIRS Study, a large primary-care screening study of HH and iron overload, we randomly assigned participants to receive brief information on either HH genotypic or phenotypic testing, and assessed the willingness to accept this test. The study was designed to recruit an equal number of African Americans and Caucasians. Results: A total of 2500 participants were recruited from waiting rooms of primary care practices; 2165 participants who self-identified as African Americans and Caucasians were included in the analyses. Overall, 56% had accepted a genotypic test versus 58% for a phenotypic test. Adjusting for Field Center (FC), age, gender, race, educational attainment, global health rating, and knowledge of the test, the odds ratio of accepting a genotypic versus phenotypic test was 0.85 (95% CI: 0.71, 1.02; P = 0.078). Characteristics associated with test acceptance were age 45-64 years, female gender, Caucasian race, self-rated health less than "very good", and knowledge of the test. Test acceptance was associated with interest in knowing more about health (81%) and in helping family members (71%). Refusal reasons included a need to talk with a doctor (44%), concern about privacy (32%), and dislike of blood drawing (29%). Conclusion: In this diverse sample of primary care patients, stated acceptance of genotypic testing for HH mutations was similar to phenotypic testing for blood iron. Patient education regarding the nature of test, importance of disease detection, and privacy protection appear to be essential for achieving high rates of screening participation.