An account is given of the therapeutic experience with lithium in childhood hyperaggressivity. In 13 cases of the hospitalized l7children between 3 and 12 years of age significant rehabilitation was achieved. Their sociability and ability to adapt themselves to the environment improved to a tolerable level. During treatment, no irreversible side effects were observed. It is recommended that the treatment should be performed either at a child psychiatric unit or by a psychiatrist with adequate experiences in this field and preferably at a hospital.