This paper reports on a qualitative study that examined English as a second language (ESL) teachers' perceptions of classroom-based reading assessments. ESL teachers' use of classroom-based reading assessments, their understanding about the function and effectiveness of this assessment method, and the factors influencing this assessment process are presented. Six middle school and 7 elementary school ESL teachers participated in this study. Data consisted of interviews with ESL teachers, classroom observations, and assessment materials teachers used in the classrooms. Constant comparative method was used for data analysis. Findings of this study include that ESL teachers highly value classroom-based reading assessments, considered them accurate and valuable and thought these assessments could provide great help to the daily teaching of reading. Teachers viewed state-mandated standardized testing negatively and of little value for English language learners. Student characteristics, statewide mandated tests, and district policies were three major forces influencing and controlling the kind of reading assessment used by teachers. The teachers' perceptions, beliefs, and uses of assessment have implications for teacher education programs and policymakers. (Contains 1 table and 1 figure.)