This paper presents the results of a study on the use of teacher work samples to assess the ability of preservice teachers (PTŐs) to meet program standards and to impact the learning of the students they teach. Unlike traditional assessments of PTŐs, teacher work sample methodology (TWSM) relies on measures of student learning as an index of preservice teacher effectiveness. The assessment approach used in this study builds upon the Teacher Work Sample Methodology first described by (Schalock, Schalock, & Girod, 1997) as a response to the report What Matters Most, Teaching for America's Future (National Commission on Teaching and America's Future, 1996). The setting of the study was a secondary school field experience prior to graduation. The PTŐs were placed in schools for 10 weeks. During this time students taught between 1-3 different instructional units. Data are reported for seven participants. This descriptive study describes the work sample tasks given to PTŐs, and reports the pre-post measures of student learning in cognitive, psychomotor and affective domains used by the PTŐs as measures of student learning. Preservice teacher perceptions of the TWSM are reported. The study also examined whether work samples could be feasibly and equitably assessed to warrant their use as a measure of teaching performance. Results of the study show initial support for teacher work sample assessment as one mechanism to provide credible evidence connecting teaching performance to student learning. Strengths and limitations of this TWSM are discussed. Findings from student interviews indicate that students were concerned with the amount of time in class that they needed to demonstrate student learning as well as the problematic nature of short units of instruction and their ability to demonstrate learning. Implications are discussed in relation to the design of teacher preparation programs and teacher assessment.