There is a rapidly growing literature concerning how children’s physical health, mental health, and regulatory skills may play a critical role in determining success during school and beyond.  Yet relatively few large-scale studies have examined current school services directly aimed at addressing children’s health needs.  In this paper, we examine school-based health centers—clinics located inside school buildings but funded by non-educational revenues and operated by local health agencies, such as hospitals.  The number of school-based health centers nationally has grown from 120 in 1988 to 1,200 in the late 1990’s to almost 2,000 today.  School-based health centers in New York City alone currently serve over 100,000 students.  Using data from New York City’s public elementary and middle schools, we explore how the openings and closings of school-based health centers have affected student attendance, test scores, and disciplinary incidents.  Preliminary results suggest that centers reduce student absenteeism, especially if the centers offer mental health services.