A simplified version of the HIVNET prototype HIV vaccine process was developed for adolescents at risk of HIV by:(1) reducing reading level; (2) reorganizing; (3) adding illustrations; and (4) obtaining focus group feedback. Then adolescents (N = 187) in three cities were randomly assigned to the standard or simplified version. Adolescents receiving the simplified version had significantly higher comprehension scores (80% correct vs. 72% correct), with 37% of items significantly more likely to be answered correctly. They were also significantly more likely to recall study benefits and procedures. Overall, adolescents were less willing to participate in a potential HIV vaccine trial after presentation than prior to presentation. The present study indicates that it would be feasible for adolescents to participate in a vaccine trial, as simplification of vaccine information, combined with illustrations to depict key concepts, resulted in improved scores for adolescents on the comprehension and recall test.