A research investigation on how teachers actually implement team teaching focused upon individual teachers and how they used the innovation. The research was based on the Concerns-Based Adoption Model. The model proposes eight Levels of Use and common to all these Levels are seven categories that represent behaviors a user at any level might be expected to demonstrate: knowledge, acquiring information, sharing, assessing, planning, status reporting, and performing. Through the use of personal interviews and limited observations, information about team teaching, or teaming, was collected from 411 teachers in 39 schools, ranging from those not involved in teaming to those who had been teaming for 5 or more years. A description is presented of the Level of Use patterns that were found. In this description, an outline presents the characteristic attitudes of users of an innovation at each level. Nine different patterns of teaming are described and briefly analyzed. The implications of the study for developing and implementing team teaching programs are discussed. (JD)