This research focused on the relationship between full-time co-teachers and the interpersonal, professional and organizational issues that had the greatest impact on their preference to remain or leave team teaching for the next school year. Most teachers indicated they would continue, in most cases it was contingent on remaining with the same partner. Teachers considered reciprocal respect, shared decisions, equity in direct instruction, similar instructional beliefs, and flexibility to be the most important interpersonal traits. Greatest professional concerns focused on sufficient co-planning time, increased staff development and in-class support specific to the co-teaching program. Teachers wanted the opportunity for inter-class or inter-school visitation and the demonstration of various teaching models conducted by personnel specifically skilled in team teaching. Research also revealed that some individuals may not be best suited to work in a shared environment. Defense mechanisms of dominance, distrust, inadequacy, submission, territorialism and hyper-sensitivity often resulted when teachers were placed in this program without appropriate screening. Therefore, administrators should use multiple factors in selecting and forming teacher teams and provide opportunity for input by current team members when selecting additional or replacement staff for the program.