Seven hundred thirty-two volunteer participants enrolled in 35 substance abuse treatment facilities across the United States were surveyed to examine the prevalence and nature of incest contacts among adults receiving substance abuse treatment. Results indicated that approximately 36% of the sample reported histories of incest: by gender, 29% of the male and 55% of the female participants reported incest histories. Data are presented regarding the age during incest contact, frequency of contacts and involvement of force, alcohol, and drugs. In addition, comparisons between incest and nonincest groups of participants are presented. Implications for substance abuse treatment facilities and staff are presented.