The purchase of single cigarettes from shops by children aged 14 and 15, to whom all cigarette sales are illegal, was studied in a survey of 3513 teenagers attending nine state secondary schools in the Bristol area. Of those children who had tried smoking only once, 5% reported having at some time purchased a single cigarette from a shop. This percentage rose to 18% in current occasional smokers of less than 1 cigarette per week, and reached 52% in those smoking more than 6 cigarettes per week. There was no difference by sex or age, but some evidence of an association with family smoking habits and with social class, and wide variation between schools. In the school with the highest incidence, 80% of regular daily smokers had at some time bought single cigarettes from a shop, compared with 14% in the school with the lowest. Only 1% of children who smoked said that buying single cigarettes from shops was their usual way of getting cigarettes. Our results imply a cynical flouting of the law by many shopkeepers who are acting straightforwardly as drug pushers.