Most community college students are referred to developmental education courses to build basic skills. These students often struggle in these courses and college more broadly. CUNY Start is a prematriculation program for students assessed as having significant remedial needs. CUNY Start students delay matriculation for one semester and receive time-intensive instruction in math, reading, and writing with a prescribed pedagogy delivered by trained teachers. The program aims to help students complete remediation and prepare for college-level courses. This article describes the results of an experiment at four community colleges (n ≈ 3,800). We estimate that over three years, including one semester that students spent in the program and two-and-a-half years after the program was complete, CUNY Start substantially increased college readiness, slightly increased credit accumulation, and modestly increased graduation rates (by increasing participation in CUNY’s highly effective ASAP).