The psychological impact of DNA predictive testing on asymptomatic individuals at risk for Huntington disease (HD) has received considerable attention since the advent of the procedure in 1993. This study examined the impact of such testing on families from the families' perspective. Individuals asymptomatic at the time of testing, together with their families, were interviewed in their homes with a semi-structured interview. Eighteen families with a total of 55 individuals participated. Defining the family as the unit of analysis was consistent with Systems Theory that links interactions of individuals, families, and the social environment. Areas of affected family functioning noted by the respondents included: 1) family membership; 2) family patterns of communication; and 3) future care giving concerns as they influenced current relationships. Eighty-one percent of families experienced changes in family membership. Members in 50% of families experienced changes in patterns of communication, and 56% percent of persons reported changes in current relationships in response to test results and their implications for future caregiving. The data support the conclusion that genetic testing is a family, as opposed to an individual, matter and that family involvement in the decision making process should be strongly encouraged in order to help families adjust. The data imply that families will benefit in pre-test sessions from an examination of their patterns of dealing with illness issues, both past and present.