Of 354 people over 65, whose names and addresses were obtained at random from local Health Executive Council lists, 109 (31 per cent) were not at the address stated. Of those whose names and addresses agreed on Health Executive Council lists and the Register of Electors, only 6 per cent were not at the address stated. This figure was confirmed by a further survey involving an additional 204 elderly people. The combination of the use of Health Executive Council lists and of the Register of Electors is suggested as being useful for survey purposes in the elderly.