Nationally, 38.5% of the students who began at a four-year college in 2011-12 attended another college within the first six years of college entry, and more than half of these students attended a community college. Eight percent of students who began at a four-year institution took up to 10 credits at a community college during the same period. Given the number of students involved, it is helpful to better understand how this kind of postsecondary enrollment pattern affects students. This paper considers a sample of "supplementally enrolled" students who began in and primarily enrolled in four-year colleges but who also earned limited numbers of credits at community colleges. We use student data from the Education Longitudinal Study of 2002 and a propensity score matching approach to compare key outcomes of four-year college students who earned 1 to 10 credits at two-year colleges during their first three years at college with those of four-year college students who never earned credits in a two-year college. Many of the supplementally enrolled students took STEM courses at a two-year college. We find that the supplementally enrolled students had higher STEM and total credits earned, higher bachelor's degree attainment, and better employment outcomes than the students who never earned credits from a two-year college. Subgroup results also suggest that supplemental enrollment can potentially improve STEM degree attainment outcomes, particularly for low-socioeconomic-status and female students.