The purpose of this study was to assess the impact of a cognitive-affective intervention the attitudes, knowledge, and anticipated professional behaviors regarding homosexuality and gay and lesbian issues of pre-service teachers in the United States. Sixty-seven participants were randomly assigned either to a control group (n=34) or an experimental group (n=33). Pre-test and post-test means were compared using paired-samples t-tests to determine the impact of the intervention. Data analysis revealed significant positive changes in the pre-service teachers' attitudes and knowledge about homosexuality, as well as their anticipated professional behaviors with respect to homosexual students and their families. (Contains 4 tables.)