The purpose of this study was to develop a questionnaire to measure elementary preservice teachers' emotions about teaching science and mathematics. To achieve this goal, a questionnaire, Teacher Emotion for teaching Science and Mathematics (TESaM), was designed and pilot and field tested with a sample of preservice elementary teachers in the United States. Using the rating scale Rasch model, results showed that the TESaM can produce reliable and valid measures of preservice teachers' emotions concerning teaching science and mathematics. Based on measures from the TESaM, we found that elementary preservice teachers had more positive emotions about teaching science than about teaching mathematics. Additionally, when comparing emotions overall, preservice elementary teachers experienced greater Anxiety than Anger and Joy over teaching both content areas. Implications for teacher educators and future research are discussed.