A Structured Clinical Interview (SCI) was used to assess both proximal characteristics of the rearing environments of prenatally polydrug exposed infants in a low SES sample and infant behavioral characteristics (e.g., feeding, sleeping, self-regulation). The 95-item questionnaire systematized collection of developmental history and caregiving environment for 132 infant-caregiver dyads who were seen for follow-up at 6, 12, and 24 months. Outcome data were indexed in five theoretically based areas: Caregiving Instability, Problems with Social Routine, Dysregulation, Infant Feeding Problems and Infant Sleeping Problems. Main effects were found in the Caregiving Instability and Sleeping Problems Index scores for drug exposure but not gestational age. Chronological age and drug interactions were found for Feeding Problems and Sleeping Problems Index scores, with those in the drug group having persistent difficulties in these areas. Additionally, there was a term and drug interaction effect in the Problems with Social Routine Index. In all of these areas, prenatal drug exposure was associated with less optimal scores. The SCI proved to be a useful tool in studying this high-risk population and may be useful in research and clinical settings. Future instrument development is planned.