Many geriatric day hospitals are under-utilized. A survey of general practitioners' opinions on referral systems to day hospitals in east Surrey produced an 85% response rate. Of the 80 general practitioners who responded 58% referred occasionally, 39% frequently and 4% never. When asked about referring patients directly to the day hospital via the coordinator instead of via the consultant geriatrician, 58% of general practitioners said they would like to have direct access, and 87% were in favour of other health workers involved with the elderly initiating referrals with the general practitioner's consent. Rehabilitation was mentioned as the main reason for referral by 76% of general practitioners, medical assessment by 56% and social care by 48%. Comments received suggested that the hospital day was too long and that early rising associated with attendance caused stress in the elderly attenders. It is concluded that the present system of referral via the consultant is not always satisfactory and that a referral card system which permits general practitioners to refer directly to the geriatric day hospital may increase utilization.