Bipolar disorder has not been well studied in prepubertal children, despite its potentially debilitating effects on growth and development. However, there have been case reports of mania in this age group dating back to Esquirol in the mid-19th century. Despite anecdotal case reports, explicit criteria to diagnose mania in children were not used until 1960. Since 1980 the DSM-III/DSM-III-R criteria have indicated adult criteria can be used to diagnose childhood mania, with some modifications to adjust for age differences. Bipolar disorder has not been frequently considered in the psychiatric differential diagnosis of children. However, if a diagnosis of mania is made, clinical rating scales can be used to rate the severity of manic symptoms and to monitor treatment. A manic child should be treated using a biopsychosocial approach. To date, lithium carbonate has been the most commonly used psychopharmacological treatment, but results have been variable. Additional research is needed, including double-blind, placebo-controlled studies to document the beneficial effects of mood-stabilizing medications. Also, diagnostic instruments should be refined to improve their utility. Finally, children at high risk for developing mania should be studied to identify predictors of bipolar disorder in children.