This article reports on the development of the Mathematics Experiences and Conceptions Surveys (MECS), a pair of comprehensive instruments designed to measure elementary preservice teachers' dispositions, attitudes, and beliefs about mathematics teaching and learning. In addition to conceptions, MECS aims to capture elementary preservice teachers' related mathematical experiences at various benchmark stages in teacher education programs. The Rasch Rating Scale Model is used to examine the psychometric properties of MECS instruments and to establish six scales that are capable of producing reliable and valid measures. Finally, we present an illustration of how MECS might be used within elementary mathematics teacher preparation.