The study utilized data from the Beginning Postsecondary Students Longitudinal Study (BPS:04/09) to examine factors that affect 4-year college students' likelihoods of completing a science, technology, engineering, or mathematics (STEM) bachelor's degree within 6 years of entering college. Results highlight the lasting influence of high school academic achievement, the importance of declaring a STEM major early in a student's college career, and disparate effects of academic performance and levels of social and academic integration. The findings suggest that students who initially may not be oriented toward STEM fields upon entering college may particularly benefit from receiving information on and encouragement toward STEM programs of study during their first year of college.