This research study examined the effectiveness of prekindergarten (PK) on kindergarten school readiness. The parents or guardians of kindergarten students at two Title I schools located in an urban school district in the southeastern United States completed a questionnaire which allowed the researcher to identify each student's participation in a PK program. Parents also signed a consent form to allow the researcher to access the kindergartener's beginning-of-year reading scores for DIBELS Next Letter Naming Fluency (LNF), DIBELS Next First Sound Fluency (FSF), and mCLASS Reading 3D Text Reading Comprehension (TRC). Responses from the questionnaire were coded into three categories: students who had attended the school district's Bluebird PK program; students who had attended PK at another location; and students who had not attended a PK program. The LEA Office of Accountability provided the researcher with de-identified beginning-of-year reading data and students' demographics that were sorted into ethnicity, gender, disability, and limited English proficiency (LEP). A hierarchical regression model was run to categorize each kindergartener's performance on DIBELS Next LNF and FSF assessments. A logistic regression model was performed to ascertain the effects of TRC scores on the likelihood that students who attended a PK program prior to kindergarten entry would demonstrate proficiency. Results indicated that attendance in the Bluebird PK program and at other PK programs had a positive effect on kindergarteners' school readiness skills.