Marital status can be a predictor for substance abuse and treatment success. Married persons may have fewer substance abuse problems than unmarried persons, show better courses of treatment when they require it, and relapse less often to substance abuse after treatment. Relationships between marital status and substance abuse treatment admissions were monitored with the Treatment Episode Data Set, an annual compilation of data on the demographic characteristics and substance abuse problems of those admitted to substance abuse problems. Data were also collected from the National Survey on Drug Use and Health (NSDUH). In 2005, 52 percent of substance abuse treatment admissions aged 25 to 44 had never married, 28 percent were formerly married, and 20 percent were currently married. By contrast, in the Nation as a whole, data from the 2000 census for this age range showed 25 percent had never married, 14 percent were formerly married, and 61 percent were currently married. Admissions who had never married were more likely than those who were formerly or currently married to report daily use of the primary substance. Substance abuse treatment admissions who had never married were more likely to have extensive treatment histories and less likely to be entering treatment for the first time than other admissions aged 25 to 44 in 2005. Figures