One of the most common questions asked about the State University System (SUS) is "What is enrollment within the SUS?" The answer to the question will depend on how and when enrollment is counted. This information brief is an effort to provide an easily accessible, written explanation of the principal methods of measuring enrollment and how they fundamentally differ. Headcount enrollment provides a picture of what the student population is like and is used for myriad state and federal reporting requirements and analyses. Full-time-equivalent (FTE), by definition, is a count of one student attending full-time for a full academic year. FTE, in reality, is a measure of instructional effort, the total credit hours taken by students. Due to the differences between headcount and FTE, one must use care when comparing Florida FTE to other states. In addition to describing the differences between the various methods of measuring enrollments, this brief also details policy and budget implications and funded versus unfunded courses. Table 1 shows State University System Fall Headcount Enrollment while, Table 2 shows State University System Full-Time Equivalent Calculated Using the Florida Methodology. Another table shows Student Headcount by Part-Time/Full-Time, Gender, Race, and Level, Fall 2005, SUS Summary, Educational and General. [This information brief was prepared by Planning and Institutional Research, Florida Board of Governors.]