Preschoolers were randomly assigned to participate in either a personal safety program or a general safety program and were then post-tested. Children listened to a vignette depicting a hypothetical personal safety violation. Following the vignette, the interviewer asked a series of questions about the victim and the perpetrator. The personal safety program produced significant gains in knowledge and skills thought to be useful in helping children avoid sexual victimization. Program participants significantly improved in their ability to recognize abuse, respond in potentially abusive situations, report secret touching, and remember key concepts. The program, however, did not affect participant perceptions of perpetrator age and gender or victim gender, the relationship between victims and perpetrators, or the possibility of abuse recurrence. Further, the program did not make children suspicious of innocuous touches and did not negatively affect their views of normal sexual behavior. Characteristics that made it difficult for children to understand child sexual abuse prevention concepts and skills were the same characteristics that made them vulnerable to abuse. Advantages of studying children's responses to personal safety programs through a developmental lens are discussed, and suggestions for additional research are offered. 48 references and 4 tables