This study investigated whether training cooperating teachers using a Praxis III/Pathwise model to frame discussions on teaching and learning would enhance development of pedagogical skills, examining the effects of mentor training on student teachers' demonstration of 19 target criteria. Student teachers were randomly assigned to field experiences either in an experimental group that used Praxis III/Pathwise training for cooperating teachers or to a control group that employed a traditional supervision approach only for cooperating teachers. Student teachers received orientation to the Praxis III/Pathwise framework. All participants provided pre-assessment data during week 1 of student teaching via a videotaped lesson using Praxis III/Pathwise support tools. Student teachers met with cooperating teachers periodically for discussions on teaching and learning. Data were gathered at midpoint and at the end of student teaching. Cooperating teachers trained in the general principles and practices of mentoring and supervision with Praxis III/Pathwise to guide interactions have more positive impact on student teacher development than those with no training. There were areas within the framework where mentoring alone was not the factor primarily responsible for differences. (Contains 37 references, 5 tables, and 1 figure.) (SM)