Symptoms of schizophrenia may be encountered in Huntington's disease (HD) but usually when the full clinical syndrome is apparent; prechoreic psychosis is relatively uncommon. We describe a family where all four members affected with HD presented first with a severe psychiatric syndrome, which in three cases was schizophreniform in nature. Two other living members with no current signs of motor disorder have received psychiatric treatment, one for schizophrenia. Concurrence of psychosis and Huntington's disease in this family is unlikely to have occurred by chance, suggesting that there is some feature in this family which gives rise to the psychotic presentation. Families such as this may contribute to the investigation of genetic factors associated with psychiatric illnesses.