UW-Madison successfully migrated more than 20 years of legacy data from a homegrown system to a purchased package, PeopleSoft's Student Administration system. UW used a phased approach to implementation, with the Admissions module going into production first. The data to be converted included legacy admissions data and the Campus Community data needed to support admissions processing. This paper describes the problems facing technical staff, tools and strategies used to solve those problems, and the (happy) result. Also included are reflections on what should have been done differently.