Thepresent study was partial replication ofastudy donefiveyears earlier whichexamined interdisciplinary teaming in middleschools andtheresulting impact of interdisciplinary teaming on student self-concepts. The degree of interdisciplinary teaming was measured using the stages-of-concern instrument that is a component of the Concerns Based Adoption Model (CBAM). Student self-concept was measured by the Piers-Harris Children's Self-Concept Scale. Results showed that the majority of teachers in Iowaschools are at the early stages of usage of interdisciplinary team teaching and usage overtime does not lead to higher levels of implementation of the concept. In contrast tothe1987 study, whichfoundstudents whoattendedmiddleschools with interdisciplinary teaming hadhigher self-concepts than middle schools in which teaming had not been implemented, this study did not find a significant difference between students in userand nonuser schools.