Many preservice primary teachers have low self-efficacy for science teaching. Although science methods courses have often been shown to enhance self-efficacy, science content courses have been relatively ineffective in this respect. This study investigated whether a tailored science content course would enhance self-efficacy. The participants were preservice primary teachers and data collection was by survey and interview. Self-efficacy increased during the course and the increases were stable after a 10-month delay period. The factors that enhanced self-efficacy were: learning science content, perceptions of learning how to teach science, and teacher enthusiasm.