An Internet tool for monitoring, personalized feedback and referral was developed to support routine adolescent preventive care and was compared with usual practice using paper and pencil (P&P). A total of 1071 students (average age 15 years) from seven secondary schools were randomly assigned to the Internet or P&P group. The Internet group received a health and health-behavior assessment, tailored feedback on health and health behavior (specifically fruit consumption), and an online referral to see a physician/nurse if necessary. The P&P group received the same assessment, preprinted generic advice on fruit consumption and a mailed referral (where applicable). Students and physicians/nurses completed evaluation forms to assess indicators of feasibility, acceptability (i.e. satisfaction) and quality of each administration mode. Student participation rate was 87%. The electronic health feedback was positively evaluated. Students perceived the Internet-tailored fruit advice as more pleasant, more personally targeted and more enjoyable, but less credible than the generic preprinted advice (P < 0.01). No differences in indicators of acceptability and quality of consultation were found (P > or = 0.05). Thus, the Internet can be a valuable tool to support physicians/nurses in the field of preventive care. It is recommended to further optimize and evaluate the Internet as a tool.