Severe child abuse in north-east Wiltshire was studied retrospectively during the period 1965-71, and prospectively for 18 months from January 1972, after a period of consultative activity with those actively involved to increase awareness of the phenomenon. Severe abuse was strictly defined. A rate of 1 per thousand children under four years old was obtained, together with a death rate of 0-1 per thousand. The families of the retrospective series of abused children were studied in detail and identifying characteristics of large family size, youthfulness, low social-class, instability, and gross psychiatric, medical, and social pathology described. The implications of the ascertainment and death rates are discussed in relation to data from some other studies, and the need emphasized for detailed studies of the apparent clustering of disorder in the families, using linked record systems.