Many members of the mathematics and science education community believe that the integration of mathematics and science enhances students' understanding of both subjects. Despite this belief, attempts to integrate these subjects have frequently been unsuccessful. This study examines the development and implementation of a team-taught integrated middle level mathematics and science methods course. The data presented in this study were collected from three groups of preservice teachers who were enrolled in a grades 5-8 middle level teacher certification program in Connecticut from 1998-2000. The data analysis indicates that preservice teachers appreciated the emphasis on integration used in the course, but at the same time when concepts did not integrate easily they were frustrated. Despite this frustration, the preservice teachers' understanding of integration was enhanced as a result of the course.