Research examining diversifying college enrollment patterns has gradually gained attention in recent years. Yet, few studies have focused on postsecondary co-enrollment and its different forms such as co-enrolling at institutions of the same level (lateral co-enrollment) and attending a 4- and 2-year institution simultaneously (vertical co-enrollment), and their distinctive relationship with baccalaureate completion and college persistence. Drawing upon data from the Beginning Postsecondary Students Longitudinal Study (BPS:04/09) and the Postsecondary Education Transcript Study (PETS:09), this study investigated the relationship between co-enrollment and baccalaureate completion and college persistence among beginning 4-year institution students and baccalaureate-aspiring beginning community college students who first accessed postsecondary education in 2003-2004. Results indicated that vertical co-enrollment appeared to have a positive relationship with baccalaureate attainment and persistence among students beginning at 4-year institutions as well as baccalaureate-aspiring community college beginners, while lateral co-enrollment did not demonstrate a significant association with attainment and persistence across both student groups. Policy implications and suggestions for future research are also discussed.