The current study examined whether field placements within an inclusive classroom are associated with improved preservice teacher's efficacy when working with children with developmental delays or disabilities. Study participants were 165 undergraduate students enrolled in primary teacher education classes at a Midwestern university. Participants responded to a modified version of the Teacher's Sense of Efficacy Scale. A significant positive correlation between preservice teachers' efficacy of working with children with developmental delays or disabilities and their inclusive field experiences was found. Findings in this study stress the need for undergraduate early childhood education programs to utilize diverse, highly inclusive classrooms in their students' field experiences; not only in the hopes of increasing efficacy, but to also develop the skills and dispositions valued by our profession.