English Language Learners (ELLs) are the fastest growing segment of school population, especially in urban schools. The teaching workforce has relatively unchanged to match this fast growth. Data found no measurable difference in the percentages of teachers' ethnic backgrounds between 1999-2000 and 2007-2008. This mismatch creates the demand for preparing the K-12 teachers who can work effectively with ELLs. The study examines an innovative program that prepares K-12 teachers through research and service combined with traditional professional development. Findings reveal significant improvement in the teachers' second language (L2) knowledge and strategies working with ELLs.