Examining how preservice teachers (PTs) perceive and implement assessment may provide clues as to how we can refocus the way future teachers use assessment. A conceptual framework addressing PT beliefs and how they change was applied in this study to examine PTs' (N = 17) beliefs and understanding of the role of assessment and evaluation on student learning and instruction while implementing a high school physical education program. PTs experienced and discussed the role of needs assessment, assessment-focused instruction, and authentic and alternative assessments in relation to student learning and instruction using a teaching for understanding framework (Wiggins, 1998). Data gathered included surveys and interviews documenting PTs' previously held beliefs and conceptions; current perceptions of the assessment concepts used during the course and in their units; analysis of assessments used in unit plans; and PTs' perceptions of assessment and student learning during and after the unit taught. PTs planned and implemented alternative/authentic as well as traditional assessments in three out of four units. PTs' beliefs about student learning and assessment were varied. Despite ultimate lack of teacher authority, PTs felt that doing these assessments affected their beliefs about assessment. Some PTs accommodated new information about authentic assessment and expanded their understanding, whereas other PTs either resisted or assimilated this new knowledge into existing belief structures. The results indicate that shaping critical and authentic assessment experiences in teacher preparation deserves increased attention and deliberate planning throughout PETE programs if shifts in beliefs are to be made. (Contains 4 tables.)