Assessing student performance is one of the most critical aspects of the job of a classroom teacher; however, many teachers do not feel adequately prepared to assess their students performance. In order to measure and compare preservice and inservice teachers' assessment literacy', two groups wee surveyed using the "Classroom Assessment Literacy Inventory" (CALI) which was designed to parallel the "Standards for Teacher Competence in the Educational Assessment of Students." Inservice teachers performed highest on Standard 3--"Administering, Scoring, and Interpreting the Results of Assessments" and lowest on Standard 5--"Developing Valid Grading Procedures." Preservice teachers performed highest on Standard 1--"Choosing Appropriate Assessment Methods" and lowest on Standard 5--"Developing Valid Grading Procedures." Comparisons between the two groups revealed significant differences on five of the seven competency areas, as well as on the total scores. In all cases where significant differences were found, the inservice teachers scored higher than their preservice counterparts. (Contains 3 tables.)