We offered cystic fibrosis (CF) carrier testing to reproductive-age enrollees in an HMO, in order to determine factors associated with test utilization in a primarily nonpregnant population. Male and female enrollees either were mailed an invitation to have the test after attending an educational session (N = 2,713) or were approached in waiting rooms at the HMO sites and given the opportunity to have the test without making an additional visit (N = 608). Uptake was considerably higher when testing could be obtained without making an additional visit (23.5%) than when attendance at an educational session was required as a prerequisite for having the test (3.7%). Utilization was higher among respondents who were planning children. Caucasians, and those with higher educational attainment. Among respondents planning to have children, individuals with higher tolerance for test uncertainty, lower fear of stigma, and higher perceived risk of being a carrier were significantly more likely to have the test. Testing decisions were not associated with the perceived burden of a child with CF or with the likelihood of aborting for CF. Although utilization of CF carrier testing is relatively low among nonpregnant individuals, uptake is significantly higher when testing can be obtained with minimal effort. Factors associated with the decision to be tested had more to do with implications of being a carrier per se than with the concerns of having a child with CF.