The aim of this article is to investigate the long-term developmental consequences of being born to a substance-using mother, focusing on cognitive functions, attention, emotional and social development. The longitudinal sample comprised 48 adolescents aged 12-16 at the time of follow-up assessments, which included the Wechsler Intelligence Scale for Children-III, the Test of Everyday Attention for Children, The Tower of London test and the Strengths and Difficulties Questionnaire. The adolescents scored significantly lower than the norms on Wechsler’s subtests and Full-Scale IQ, and on The Everyday Attention test. There were few differences on the Strengths and Difficulties Questionnaire. The girls reported significantly more hyperactivity than the British norms, and the teachers reported higher impact scores in boys, compared to the British norms. Thus, the results on cognitive consequences of maternal substance use appear to be very substantial while the emotional and social consequences do not. The results suggest serious negative effects of substance exposure in utero on attention and cognitive functioning in general.