The effectiveness of curricula designed to enhance a child's understanding of AIDS may hinge partially upon incorporating information adjusted to the child's developmental status. Accordingly, we examined the developmental progression of children's understanding of illness transmission in general and AIDS in particular, as well as explored the relation between a child's knowledge of AIDS and his/her attitudes toward persons with AIDS. Knowledge of AIDS was manipulated through use of a brief educational intervention. Results support a developmental progression in knowledge about AIDS that is consistent with progressions related to illnesses in general. Knowledge enhancement was associated with positive changes in attitude.