Tracking is a predominant method used by American public schools to instruct children of multiple abilities. Tracking has been highly criticized by scholars, however, for its detrimental effects on children's education. This paper investigates practitioners' rationale for using tracking and explores the effects of tracking in the classroom and on students. The study consisted of observations of four fourth-grade classrooms, interviews with their four teachers, and surveys of 30 fourth-grade students in an elementary school in central Virginia. Although these students were grouped into four homerooms, they were taught mathematics in five ability groups. The results partially support the literature that suggests that teachers prefer tracking because it facilitates instruction. Further analysis suggests that tracking may appear to have degenerating effects on children, particularly on their self-perceptions. However, due to the limited scope of the study most of the findings remain inconclusive. Recommendations are proposed for future research of the tracking issue. Appendixes contain the assessment used to place the students in mathematics groups, the teacher interview questions, and the student questionnaire used in the survey. (Contains 11 references.) (SLD)