Prenatally drug-exposed toddlers were compared to preterm toddlers of similar low socioeconomic status, ethnicity, and single-parent households on intellectual functioning, quality of play, and security of attachment to the primary caregiver. The drug-exposed toddlers had significantly lower developmental scores, less representational play, and the majority had insecure, disorganized, avoidant attachments. In all areas investigated, the prenatally drug-exposed toddlers showed more subtle behavioral deficits within each domain. Although developmental quotients were within the average range, they were significantly lower than the preterm comparison group and did not adequately represent the more evident deficits seen through play in an unstructured situation. Unstructured assessments that required the child's initiation, goal setting, and follow-through were more revealing of developmental disorganization within and among domains than were adult structured assessments such as developmental tests. While modest differences were seen in structured tasks, the marked differences between the drug-exposed and preterm groups were most evident in the unstructured tasks. The lack of coherence across developmental domains was illustrated by the large difference between developmental quotient scores and the poor performance in the cognitive representional competencies demonstrated in play. Insecurity and disorganization in attachment were found to compromise further the development of the drug-exposed toddlers.