The dispositions of preservice elementary education teachers toward reform-oriented mathematics education were surveyed before and after an extended pre-student teaching practicum. During the practicum, university and school-based personnel served as 'clinical faculty' as they supported the preservice teachers' practicum experiences. The preservice teachers' perceptions of the clinical faculty's dispositions were also surveyed. Relationships between changes in the dispositions of the preservice teachers and their perceptions of the clinical faculty were discovered, thus highlighting the important influence clinical faculty wield as mathematics teacher educators.