There is mounting concern among professionals in special education about where students with special needs receive services. The relative dearth of empirical data to guide states, school districts, and teacher preparation programs as teacher roles and instructional responsibilities are redefined is sorely evident. In this study, a factor likely to affect student achievement in special and general classrooms was evaluated. Caseloads were examined for teachers of students classified as seriously emotionally disturbed/behaviorally disordered to compare current service delivery across states and to evaluate hypothetical predictions of student achievement based on different teacher-pupil ratios. The average special education caseload was lower than the student/teacher ratio reported for regular education; the average number of seriously emotionally disturbed/behaviorally disordered students per teacher ranged from 3.1 to 35.0. Based on these figures, hypothetical relations between caseload and predicted student achievement were evaluated. As caseload increased, predicted achievement decreased (in z-score units) and practical differences were evident between states with large differences in caseloads. Implications of the present and suggested future studies are offered.