Alcohol and other drug use during pregnancy represents a major public health concern. This article characterizes a sample of 240 pregnant opioid- or cocaine-dependent women enrolled in the initial residential component of a comprehensive substance abuse treatment program for pregnant women. Data were collected using the Addiction Severity Index, Psychosocial History Form, and Structured Clinical Interview for DSM-III-R. Patients' substance use history, psychiatric comorbidity, social support network, employability, current and previous pregnancies, child custody arrangements, and the father of the current pregnancy, are described to assist providers in tailoring treatment to the specific needs of this population.