1. In a survey of Huntington's Chorea within the Scottish Western Regional Hospital Board area, 124 affected persons were examined and information about another 594 cases obtained.
2. The minimum prevalence of the condition in 1960 was 5·2 per 100,000.
3. Some of the factors affecting first hospital referral and survival after final hospital admission in the patients are discussed.
4. The commoner clinical features and abnormal patterns of social behaviour are indicated.
5. The frequency and type of misdiagnoses are indicated, and some of the factors involved are discussed.
6. The clinical pictures in two children with onset under 10 years and 18 adults with onset over 60 years are outlined.
7. Presentation of the illness as a functional psychosis and with delayed or absent chorea is discussed.
8. Possible premonitory symptoms are indicated, and attention is drawn to the desirability of registration of cases.