This study examined the influence of the duration and frequency of a baseline episode of participation in Alcoholics Anonymous (AA) among 473 individuals with alcohol use disorders on 1-year and 8-year outcomes and the effect of additional participation and delayed participation on outcomes. Compared with individuals who did not participate, individuals who affiliated with AA relatively quickly, and who participated longer, had better 1-year and 8-year alcohol-related outcomes. Individuals who continued to participate, and those who continued longer, had better alcohol-related outcomes than did individuals who discontinued participation, but individuals who delayed participation in AA had no better outcomes than those who never participated. In general, the frequency of participation was independently associated only with a higher likelihood of abstinence.