The primary goal of this study is to rigorously evaluate the effectiveness and costs of two contrasting approaches to organizing and structuring substance abuse treatment for women entering welfare-to-work programs. One approach will deliver standard care. The alternative approach will deliver care based on an innovative, public health model. Evidence-based interventions will serve as the core components of the innovative approach. The context of this study is a naturally occurring experiment. The State of New Jersey is conducting a welfare demonstration project in two counties. Women in welfare-to-work programs with substance abuse problems will be randomly assigned to two intervention conditions, standard care or innovative care. This study will evaluate the two-year outcomes of the demonstration project. In addition, the study will compare outcomes and costs of the substance abusing women in the demonstration with those of a comparison group of non-symptomatic women in welfare-to work programs. The study sample will consist of 600 women diagnosed with DSM-IV substance abuse only, and 600 women diagnosed with DSM-IV substance dependence who are participants in the demonstration. In addition, 200 non-symptomatic women in welfare-to work programs will be studied. All study participants will be recruited at two welfare offices, assessed at baseline, and followed in-person at 3, 6, 12, 18, and 24 months. The study will examine treatment utilization patterns, and substance abuse, employment and other psychosocial outcomes. In addition, a full cost study including cost-effectiveness and cost-benefit analyses will be conducted.