The purpose behind this publication was to determine if significant differences existed in school readiness for kindergarten and growth in school readiness at the end of kindergarten between 266 kindergarten students, in an urban school district in southeastern Pennsylvania, by the type of pre-kindergarten experience. Additional variables examined demographics, discipline referrals, absences, days tardy to kindergarten, and kindergarten teacher perceptions of student readiness for kindergarten. This book provides strong evidence that the type of pre-kindergarten experience influences students' readiness for kindergarten. Analysis suggested significant differences among public school pre-kindergarten students and other groups in: readiness for kindergarten; across ethnic groups; by mother's educational level; by discipline referrals in kindergarten; absences in kindergarten; teacher perceptions of students' readiness for kindergarten.This research has significant implications for public policy and funding of education, school district practice and program development, and research on public school pre-kindergarten programs.