Two percent (N = 21) of a large sample of preschool children were identified as "pervasively hyperactive." Compared with nonhyperactive preschoolers, these children more often came from families with high levels of adversity, and they showed poorer language skills. Over a 12-year follow-up period, the hyperactive preschoolers continued to show poorer cognitive skills, lower levels of reading ability, disruptive and inattentive behaviors at home and at school, and higher rates of DSM-III disorder in preadolescence and adolescence. By age 15, only one-quarter of this group were identified as having met "recovery" criteria. The findings point to the long-term adverse consequences of preschool hyperactivity and indicate the need for intervention with this type of disorder.