The motivation of people who seek advice about a family history of cancer was explored in a cross sectional study of new cancer referrals to five regional cancer genetics centres in England: the PACT (patient and clinical team) psychosocial study. One hundred sixty-two people took part. Measures were source of referral, estimated and perceived cancer risk, level of cancer worry, and personal and family-centred reasons for wanting to be seen in clinic. General practitioners referred more people than hospital doctors, and referred a larger proportion of people at low genetic risk of developing cancer. More than half of the participants had been the first to raise the issue of their family history of cancer. Personal motivation for referral is clearly different for those who have had a diagnosis of cancer and for those with children, compared to unaffected and childless people, and is characterised by altruistic concern for other family members rather than a perception of increased personal risk. Men and people from ethnic minorities are very significantly under-represented. Understanding people's motivation may be useful in targeting genetic counselling for people with a family history of cancer.