OBJECTIVES: Despite the contribution of awareness campaigns to the rise of organ donation rates in Brazil, younger folks are subject to few awareness actions. Records on the effect of informative campaigns at improving opinion and knowledge of undergraduates about organ donation are scarce. This study aimed to assess the effect of informative material about organ donation on changes in the trend of answers to a questionnaire compared to the answers of a control group. METHODS: Two randomized groups were compared, receiving the same standardized questionnaire. One group was supplied informative material on the subject, while the other was not. The questionnaire was sent to undergraduate students from two Brazilian universities. Statistical analysis was performed using Student’s t-test, Chi-square test and multinomial regression tests. Adopted significance was 5%. RESULTS: There were 739 responses to the questionnaire. Mean age was 22 years, with a majority of women. Six of 14 questions displayed a change in the answer pattern of the experimental group compared to controls (p<0.05). Opinion on organ donation had changes in 2 of 7 analyzed questions (p<0.05). Knowledge on the subject had a shift in answer patterns in 4 of 7 questions. Regression demonstrated 3 items that were not influenced by respondents’ age. CONCLUSION: There is controversy regarding the benefit of exposure to informative material. Negative changes were noted in the trust in transplantation as a safe treatment. Positive results regarding technical knowledge were obtained. Better results may be obtained by designing informative material tailored towards the student’s specific concerns.