This study compares the retention rates of urban teachers in the Baltimore City Public School System who were recruited through a federal program called Teach for America (TFA) and selected alternative certification programs, with those of certified teachers and teachers who do not possess regular teaching credentials. The authors researched whether TFA teachers have lower retention rates than new, regularly certified teachers in urban districts. During the first two years after their hiring date, teachers in alternative certification programs were notably more likely to remain with the system than either certified teachers or conditionally certified teachers not involved in programs. While most of the TFA teachers tended to leave by the end of year three, teachers in other alternative certification programs remained with the system at higher rates than regularly certified teachers through years four and five. Three-year retention rates for TFA were as high as three-year retention rates for certified teachers in the Baltimore City Public School System for three of the four cohorts studied. This study shows the importance of urban school districts working closely with local colleges and universities to provide the type of professional development needed for alternatively certified teachers, and demonstrates that a quality, collaborative, effort can result in teacher retention rates that exceed the average. (Contains 1 table, 7 figures and 2 endnotes.)