Objectives: Children are often considered a primary motivator for women seeking substance abuse treatment. This study tested a model predicting treatment motivation in substance-abusing mothers. Methods: This study was a secondary analysis of the Drug Abuse Treatment Outcome Study (DATOS). It used structural equation modeling to describe factors influencing motivation for treatment. DATOS is a national study of substance abusers entering treatment. Treatment was provided by a sampling of community-based programs, free-standing hospitals, hospital units, county-funded programs, modified therapeutic communities, and criminal justice programs. The subsample of women with children under the age of 18 for whom custody of children could be determined was selected (n=1371). The variables comprising each factor were based on self-report, and standardized scales measuring level of drug involvement, psychological functioning, children, and a desire to stop using drugs were used. Results: Drug involvement was positively related to poorer psychological functioning, child custody issues, and the desire to stop using drugs. Child custody issues had a negative influence, while poorer psychological functioning and a desire to stop using drugs positively influenced treatment motivation. Conclusions: The negative influence that children have on treatment motivation may reflect the practical or emotional difficulties of having to leave children behind or in some instances having children placed in foster care. Specifically, losing custody of children, particularly with little expectation they will be reunified, may serve as a detriment to motivation. Popular beliefs hold that children serve as a primary source of a mother's treatment motivation; however this study found the opposite was true. Children should not automatically be considered a primary source of motivation for participation in treatment.