Teacher preparation for elementary education often separates pedagogical approaches by content. This study examines an integrative pedagogical approach in the areas of Science, Technology, Engineering, and Math (STEM) with elementary education majors. The preservice teachers were provided experiences to learn about pedagogical approaches for STEM integration and to design and implement interdisciplinary units with robotics in classroom settings as a part of a combined math and science pedagogy course. A modified version of the Science Teaching Efficacy Beliefs Instrument (STEBI-B) survey was used as a pre-and postassessment to determine if changes occurred in the preservice teacher's self-efficacy and outcome expectancy with elementary students as a result of this approach. Findings between pre-and post-assessments show increased means for both subscales: Personal STEM Teaching Efficacy (PSTE) and STEM Teaching Outcome Expectancy (STOE). Qualitative responses also indicate the beliefs and outcomes in STEM teaching were positively impacted. These findings indicate that a combined science-mathematics pedagogical approach that includes the development of units and teaching the units in authentic classrooms leads to more confidence in STEM teaching. The approach utilized in this study may serve as a model for other teacher preparation programs.