Using data gathered prospectively, the authors examined whether transitions in two major adult social roles, marriage and parenthood, influence the risk of developing (1) DSM-III-R alcohol disorder and (2) symptoms of alcohol disorder. Additionally, the potential impact of these transitions on persistence of alcohol disorder was examined. In the study, 1,007 members (21 to 30 years old) of a large health maintenance organization located in southeast Michigan were interviewed initially in 1989, 979 of whom were reinterviewed in 1992. Incidence of alcohol disorder symptoms was significantly higher among those who remained single (RR = 2.1) or became divorced (RR = 6.0) during the follow-up period, compared to those getting or staying married. Those who were never parents through the follow-up were also at increased risk (RR = 2.5), relative to those who became parents for the first time. Similar results were obtained for the incidence and persistence of an alcohol disorder. Transitions into adult roles, such as marriage and parenthood, appear to reduce the risk of developing alcohol disorder or related symptoms in young adulthood. These transitions also reduce the likelihood that an existing alcohol disorder will persist.