For well over a decade school districts across the United States have struggled to recruit and retain effective mathematics teachers. In response to the need for qualified math teachers and the difficulty of directly recruiting individuals who have already completed the math content required for qualification, some districts, including Baltimore, Philadelphia, Washington, D.C., and New York City, have developed alternative certification programs with a math immersion component to recruit otherwise well-qualified candidates who do not have undergraduate majors in math. This article examines the qualifications, student achievement gains, and retention of Math Immersion teachers in New York City compared to New York City mathematics teachers who began their careers through other pathways. (Contains 3 figures, 13 tables and 21 notes.)