Two-year public colleges serve roughly one-third of undergraduate students in the United States, and, like other types of colleges across the country, they face shifting population demographics. Additionally, completion rates at two-year institutions have received political and scholarly attention within states and across the nation in recent years. This study examined how the proportion of adult students, those 25 or older, influenced the graduation rates of two-year, public institutions. Based on multiple regression techniques using data from the Integrated Postsecondary Education Data System (IPEDS), the results of the study indicated that graduation rates decreased by less than 1% when the proportion of adult students increased by 1%. The results also revealed a negative relationship shared between graduation rates and the proportion of female students, part-time students, and the Pell Grant recipients.