One hundred forty-one individuals with autosomal dominant polycystic kidney disease (ADPKD) and 137 at-risk individuals from 107 kindreds answered a questionnaire to determine knowledge and attitudes about ADPKD and the use of gene linkage analysis for prenatal and postnatal presymptomatic diagnosis. Both groups of individuals displayed a high level of knowledge about the disease. Although 87% of affected individuals considered the recurrence risk of ADPKD high, only 11% of ADPKD did not have children for this reason after diagnosis. Ninety-seven percent of at-risk individuals would utilize gene testing for themselves. Eight-eight percent of ADPKD and 89% of at-risk individuals would test offspring (not significant, NS) and 65% of ADPKD and 50% of at-risk individuals between the ages of 18 and 40 would use prenatal testing (NS). Only 4% of ADPKD and 8% of at-risk individuals between the ages of 18 and 40 would terminate a pregnancy for ADPKD. A greater percentage would terminate a pregnancy for a serious medical problem. The factors influencing presymptomatic testing were analyzed. The data suggest that presymptomatic testing will not substantially modify incidence of ADPKD since it may only occasionally alter reproductive plans.