Objective: To identify correlations between clinical and neuroimaging features in sporadic chorea and to explicate the evolution of choreas of differing aetiologies. Methods: We analysed the clinical and neuroimaging data of 51 consecutive cases (17 males, 34 females; age 16–95 years) of sporadic chorea admitted to the neurology departments of two general hospitals from January 1994 to December 1999, and two neurological institutes from January 1997. Six months later the patients were reassessed clinically and those still with chorea (20 cases) were asked to undergo the genetic tests for Huntington's disease and dentatorubropallidoluysian atrophy. Results: There were 9 cases of focal dyskinesias, 18 of hemichorea, and 24 of generalised chorea; onset was acute in 17, subacute in 27, and insidious in seven. Analysis permitted classification as follows: vascular-related (21 cases); vasculitis (1 case); hypoxia (2 cases); drug-induced (7 cases); AIDS-related (5 cases), borreliosis (1 case); Sydenham's chorea (1 case); hyperglycaemia (2 cases); hyponatraemia (2 cases); Huntington's disease (HD) (5 cases) and acanthocytosis (1 case). In 3 patients neither etiological factors nor neuroradiological alterations were found. Conclusions: Although a convincing concordance between choreic signs and neuroradiological findings was possible in 4 patients only, it was possible to assign an aetiology in most cases with vascular related causes the most frequent and metabolic factors often participating. Huntington's disease is not unusual as a cause of sporadic choreas. HIV infection is an emerging cause of chorea and AIDS-related disease should be considered in young patients presenting without a family history of movement disorders. We emphasize the importance of follow-up to identify persistent chorea for which genetic testing is mandatory.