In preparation for a physician intervention trial to determine the effectiveness of treatment of alcoholism in a primary care setting, a study was conducted to determine patient reaction to a masked alcohol screening questionnaire. The disguised questionnaire was developed to improve the accuracy of self-reported drinking behavior and facilitate blinded randomization to an intervention and control group. Patient reaction was determined by a face-to-face structured interview. The interview was structured to elicit responses before and after the patient was informed of the true nature of the questionnaire. The sample consisted of 21 alcoholic and 33 nonalcoholic patients in a primary care clinic. Seventy-five percent of the respondents were comfortable not being fully informed when research procedures involve the use of disguised alcohol questionnaires. There was some discomfort over the deceptive nature of the questionnaire, but 83% of the subjects believed the deception was justified and necessary. Males and alcoholics in the sample were more comfortable not being fully informed about research procedures suggesting greater trust in the medical profession. Females, on the other hand, were more concerned than males about how a family member would react to the disclosure of family health information. Alcoholics and persons with only a high school education felt the use of disguised questionnaires improved their accuracy significantly more often than nonalcoholics or individuals in the sample who attended graduate school.