The development of a presymptomatic test for Huntington Disease (HD) has enabled some persons at risk to determine whether or not they are gene carriers. The purpose of this study was to explore the reasons why those at risk choose not to be tested in a situation where testing is available and most of the test-associated costs are covered by state funding. Subjects were also asked their levels of knowledge about testing, attitudes towards aspects of the testing protocols, and intentions towards testing once the gene for HD is found. Sixty-six individuals at risk for HD who had chosen not to be tested completed a mailed questionnaire. The most important reasons for not being tested were increased risk to children if one was found to be a gene carrier, absence of an effective cure, potential loss of health insurance, financial costs of testing, and the inability to "undo" the knowledge. Individuals comprising this sample were quite knowledgeable about predictive testing. Most supported the availability of testing despite the lack of a cure, the need for special counseling prior to testing, and the idea that testing should be a voluntary decision. Most said they would take the test if a treatment was available, if the mechanics of the test were simplified, or if the test was 100% accurate. The risk to relatives, lack of treatment or cure, fear of losing one's health insurance, and the accuracy of the information to be gained from testing are important factors in the decision not to be tested.