Consistent school attendance is a key foundation of student learning. While missing one or two school days each year is not likely to have serious consequences, chronic absenteeism (missing 10% or more of enrolled school days) can seriously undermine the learning process (Allensworth & Easton, 2007). Given national efforts to increase the enrollment of at-risk children into high quality early education programs, understanding whether enrollment alone is sufficient for preparing students for kindergarten or whether regular attendance also matters is an important issue with direct policy implications. This research study focused on 4-year-old children served by school-based preschool programs in a large, urban district between 2008-09 and 2011-12. The findings showed that chronic absenteeism was common among preschool students. The students who miss the most school are those who enter with the weakest skills and end up even further behind at the end of the year. Schools' abilities to organize themselves in ways that support preschool attendance may be key to preventing later attendance and learning struggles. For example, a weekly e-blasts to preschool teachers could provide reminders about the value of good preschool attendance and tips for how to keep an emphasis on good or improved attendance. Tables and figures are appended.