The purpose of this study was to explore the impact of an integrated science and mathematics methods course on preservice early childhood teachers' efficacy beliefs for integrating these content areas. Thirty-four preservice teachers participated in this study, which utilized a quasi-experimental design with two treatment groups. Participants in two cohorts were tested to assess their efficacy beliefs for teaching science, mathematics, and integrated science and mathematics before and immediately after instruction that lasted 8 weeks. Results indicated a statistically significant change in preservice teachers' efficacy beliefs scores from pre- to posttest measures. These results provide evidence that the methods course utilized in the present study was effective in enhancing preservice teachers' efficacy beliefs for integrating science and mathematics. (Contains 2 tables.)