To assess the frequency of bites by the Blandford fly, a postal survey was carried out at the end of the 1993 biting season. Questionnaires were sent to a random sample of 1,500 people, selected from the lists of the two general practices in Blandford Forum, and satisfactory replies were obtained from 1203 (80%). Altogether, 194 (16%) of subjects reported one or more insect bites, during the 2-month season, that had led to skin swelling more than 2.5 cm across. Of these, more than a quarter had suffered associated systemic symptoms, in the form of fever or joint pain. One hundred and forty-nine had used medications for bites, 20 had consulted a doctor, and seven had taken time off work or school. Bites were more common in females (22%) than males (9%). This difference was due largely to a higher frequency of bites on the legs. Risk might be reduced substantially in women by wearing trousers, especially in those who spend a lot of time outdoors.