OBJECTIVES In this study, we test the effectiveness of involving parents in school-based AIDS education with respect to altering AIDS-related knowledge, attitudes, behavioral intentions, communications patterns, and behavior of students. METHODS Fifteen high risk school districts (pre-test N = 2,392) were randomly assigned to one of three conditions: parent-interactive (classroom curricula + parent-interactive component); parent non-interactive (classroom curricula only); control (basic AIDS education ordinarily provided by the school). Students were tested over time in grades 7, 8 and 9. RESULTS Results indicate that both treatment conditions (parent-interactive and non-interactive) had a strong positive impact in enhancing student's knowledge, attitudes, communication patterns and behavioral intentions. Further, results indicate that there were no behavioral outcome differences between the treatment groups and the control condition. Results demonstrate few outcome differences between the two experimental conditions. CONCLUSIONS In the two treatment groups (parent-interactive and parent non-interactive), the program effects appear to be the result of school-based curricula and of student self-determined intentions and behaviors, rather than the presence or absence of planned parental involvement. Whether or not structured or planned parental involvement becomes part of a school-based educational activity should perhaps be determined by (a) the existing level of parent-school interaction based on the nature of the community, (b) the amount of money readily available to follow through on a program of parent involvement without compromising on student programs, (c) the age of the child and the sensitivity of the issue, and (d) the ability of the parent/family to be involved effectively without extraordinary expense or sacrifice by either parent or school. Our findings speak to the positive role of the school regardless of parent participation.