Thanks to extraordinary and exponential improvements in data storage and computing capacities, it is now possible to collect, manage, and analyze data in magnitudes and in manners that would have been inconceivable just a short time ago. As the world has developed this remarkable capacity to store and analyze data, so have the world's governments developed large-scale, comprehensive datafiles on tax programs, workforce information, benefit programs, health, and education. Although these data are collected for purely administrative purposes, they represent remarkable new opportunities for expanding our knowledge. We describe some of the benefits and challenges associated with the use of administrative data in education research.