In a drug use survey of 457 final-year medical students a self-administered questionnaire included the controversial question whether such questionnaires should be onymous or anonymous. Definite answers either in favor of or against anonymity were given 216 respondents. Of these, 72.2% were in favor of anonymity, only 27.8% favored onymity. Among those who provided ambiguous answers, or who did not respond on the issue of anonymity vs. onymity, there were significantly more drug users. Where there was no family history of drug use, or where parents definitely disapproved of drug use, a high proportion of respondents were in favor of anonymity.