Reform has transformed traditional entitlement to cash welfare under Aid to Families with Dependent Children (AFDC) into a transitional program known as Temporary Assistance to Needy Families (TANF). Because of the new work requirements and the time-limited nature of assistance, policy makers are increasingly confronted with what to do when welfare recipients do not effectively make the transition from welfare to work. Increasingly, the language of public health is being used to determine who is“employable” and who is not. Thus renewed attention is being focused on the individual characteristics of participants themselves,particularly specific diagnoses that might reduce employability. This article focuses on substance abuse and mental health problems among single mothers and examines their relationship to welfare receipt. We analyze data from the 1994 and 1995 National House-hold Survey of Drug Abuse (NHSDA) and find that 19 percent of welfare recipients meet the criteria for a DSM-III-R(Diagnostic and Statistical Manual of Mental Disorders, third edition revised) psychiatric diagnosis. About the same percentage have used illicit drugs during the previous year. Logistic regression results indicate that mental and behavioral health problems that are significant barriers to self-sufficiency are increasingly important in this era of time-limited benefits.