Travel histories were taken from 1111 British travellers. Serological testing showed that increasing age and a past history of jaundice were associated with a greater likelihood of travellers being immune to hepatitis A. Neither travel to nor the duration of stay in areas of increased hepatitis A endemicity influenced the level of hepatitis A immunity. It is concluded that travel histories from British citizens normally resident in the U.K. cannot be used to identify those travellers in whom serological prescreening would be of value prior to immunoglobulin prophylaxis.