The downward enrollment trend shown in this year's "AS&U" 100--a compilation of the nation's 100 largest school districts--is unmistakable. Added together, the 100 largest districts had 10,708,137 students in 2006-2007, compared with 10,763,959 in 2005-2006. Even districts that showed steady growth throughout the 1990s and the early part of this decade are dealing with stagnant or declining enrollment. This article presents a summary of the enrollment data of the nation's 100 largest school districts for 2006-2007.