The discovery of DNA markers linked to the gene causing Huntington disease (HD) has allowed the development of predictive testing programs for persons at-risk. A pilot program was established in British Columbia in November 1986. Ninetyfive persons are currently enrolled. The major objective of this project is to introduce and evaluate a protocol for the delivery of test results to persons at-risk for HD. The criteria for entry and details of the psychosocial assessment before and after receiving a modified risk are presented. The guidelines that are developed from this project will have major applications for predictive testing programs for other late onset autosomal dominant disorders.