EPIDEMIOLOGICAL aspects of clinical cancer of the cervix in Aberdeenshire were discussed in the preceding article (Aitken-Swan and Baird, 1966). This paper presents the results of a supplementary study of social and environmental factors thought to be of significance in the aetiology of the disease. Three groups of women were interviewed by one of us (J.A.-S.).Patients with clinical cancer: These were Aberdeenshire patients first attending hospital during the years 1961-63. Through the co-operation of Professor James Walker, numbers were augmented by the inclusion of all patients living in the city of Dundee who first attended a hospital there between 1958-63 and who were available for interview.Patients with pre-clinical cancer: Since April, 1958, gynaecological and obstetrical patients, women attending various clinics or registered with certain general practices in the city have been screened by a cytological team based on the University Department of Obstetrics and Gynaecology. The opportunity was taken to interview the first 143 ever-married women with pre-invasive cancer (sometimes known as carcinoma-in-situ) or microinvasive cancer of the cervix diagnosed by cytology and subsequent histology. Later, 57 women living in country districts were added, bringing the total to 200.A control group without cancer: These were selected from ever-married women taking part in the cytology campaign, matched to the group with pre-clinical cancer for age, number of pregnancies, city or country residence and source of contact with the campaign (post-natal clinic, gynaecological ward, general practice, etc.) Seventy per cent could be matched in all particulars, 27 per cent differed by one year of age only and 3 per cent differed by more than this. The factors considered include age, marital state, coitus, marriage and pregnancies, circumcision and contraception. Some of these factors could be studied in patients who were not interviewed, as a detailed obstetrical history and certaini social data were routinely recorded in the medical case-notes. Interviews were at the woman's home by appointment. Numbers are as follows: Total Interviewed