The authors' objectives were to improve human papillomavirus (HPV) vaccine educational materials and to determine whether parents who received those materials had improved attitudes about the vaccine. Pretests were sent to 411 parents of girls 11-18 years of age who had not yet received the HPV vaccine. The authors then randomly assigned 270 respondents to an intervention (educational flyer and posttest) or comparison (posttest only) group. The authors conducted a mixed-method analysis of intervention group feedback on improving the flyer and used paired t tests and analysis of covariance to describe within- and between-group attitude changes. The overall posttest response rate was 76%. Among intervention group respondents (n = 131), 88% had a positive impression of the flyer, and 43% reported that it made them more likely to vaccinate their daughters with HPV vaccine in the future. Parents who received the flyer also showed a statistically significant increase in mean attitude scores regarding perceived HPV vaccine safety and access to HPV vaccine information; mean scores also increased among the comparison group, but the changes were not statistically significant. Educational materials improved HPV vaccine knowledge and attitudes among parents and might have helped motivate some parents to have their daughters vaccinated.