Recent accountability efforts at state and national levels highlight the importance of preparing future teacher in the skills required to produce sound classroom assessments that are capable of improving student learning through informed instruction. Stiggins (1995) suggests that the quality of classroom assessments will not improve unless teacher candidates are trained to apply the key principles of assessment literacy when creating classroom assessments. Problem-based learning methods have been recommended as an effective strategy for training preservice teachers in a number of classroom skill areas (Sears, 2003). Teacher work sample methodology is one type of problem-based learning activity that offers preservice teachers practice in applying the principles of assessment literacy when creating assessments for a unit of classroom instruction. This case study evaluated the effectiveness of teacher work sample methodology as a strategy for teaching the principles of assessment literacy for 41 preservice teachers enrolled in an introductory assessment class. (Contains 3 tables.)