Despite good career prospects in science, technology, engineering, and mathematics (STEM) fields, persistence of students in STEM fields of study at the community college and transfer to universities to pursue STEM majors is often quite low. Theories of persistence emphasize the importance of engagement, integration, validation, and financial assistance. The DCCCD STEM Institute is a comprehensive cocurricular program for community college STEM students. It illustrates the application of persistence theories in a multicollege urban district with a diverse student body. The STEM Institute uses a student/faculty cohort model with mentoring, professional skills programming, and scholarship support to transform student perceptions of themselves, integrate them into a STEM educational community, and validate their membership within that community. Institute membership also reduces isolation and financial concerns as potential barriers to persistence. STEM faculty also participate in professional skill development through a cross-college and cross-disciplinary cohort. Data on students who participated in the DCCCD STEM Institute from 2010 through 2014 show that 92% remain in a STEM educational or career pathway. Important practice implications for community college professionals include (1) forming student and faculty cohorts, (2) facilitating the development of mentoring relationships, (3) providing adequate centralized staffing, and (4) integrating resources and opportunities into a unified cocurricular program.