Data are presented on 157 newborn infants followed sequentially in a randomized home-based nursing-intervention trial for drug-exposed infants with follow up at 3 (N=118), 6 (N=124), and 12 months (N=77). The objectives of this study were to describe the longitudinal neurodevelopmental status of a cohort of children with intrauterine exposure to illicit drugs during their gestation, characterize the evolution of early tone abnormalities in a polydrug-exposed cohort, and determine whether neuromotor outcome is associated with drug-exposure patterns. For analysis, infants were grouped based on maternal drug-use pattern and the presence of drug metabolites in the neonatal drug screen. The sequential neuromotor examination was used at each age to define the neuromotor status of six domains and define categorical classifications as either normal, suspect, or abnormal. Multiple patterns of neuromotor abnormalities were observed during the neonatal period; most resolved over time. Axial hypotonia was a prominent finding in the neonatal period; however, it was infrequent in abnormal examinations at 12 months. Increased lower-extremity tone was a less frequent finding during the neonatal period. Infants whose neonatal urine drug screen was positive for both cocaine and opiates, were more likely than infants with negative urine drug screens, cocaine only, or opiate only drug screen results to have abnormal neuromotor examinations; while positive maternal drug screens for concurrent cocaine and opiate use were associated with peripheral hypertonia. Persistence of increased leg-extensor tone was found in 67% of the abnormal examinations at 12 months. Acquisition of rolling and walking was delayed in the drug-exposed cohort.