Differences in responses by ethnic group to The Drug Abuse Problem Assessment for Primary Care (DAPA-PC) were examined. The DAPA-PC is a self-administered (via computer), internet-based screening instrument with automatic scoring, patient profile for medical reference, and unique motivational messages. Results indicate differences between blacks and whites on responses to several items in these instruments. Differences in drug use were also found between the two ethnic groups in hair/urine results. The screening criteria for the DAPA-PC instrument appear to work for both the groups in this study. Differences in responses to alcohol and drug screening instruments by ethnic group should be taken into consideration when designing screening instruments for alcohol and/or other drug use and these instruments should be adapted for different ethnic groups, when necessary. The results of this study suggest that the DAPA-PC instrument is a useful alcohol and drug abuse screening instrument for both the blacks and whites in a primary care population.