BACKGROUND. The new contract for general practitioners, introduced in 1990, required them to offer an annual assessment, or 'health check', to patients aged 75 years or more. AIM. A study was undertaken to collect details of practice organization of these assessments, general practitioners' and practice nurses' experience of assessments, and their views of the value of such assessments. METHOD. A nationwide postal survey of 1000 general practitioners and interview surveys with general practitioners and practices nurses from 150 practices were carried out in 1992. RESULTS. The postal survey yielded a response rate of 69% and the interview survey a practice response rate of 76%. Organization of assessments varied enormously between, and often within, practices with a variety of methods of invitation and assessment instruments being used. Of general practitioners 13% did not use a letter of any sort to invite patients to attend, and many doctors excluded certain patients from assessment, particularly those who were seen regularly or had been seen recently. However, 70% of general practitioners estimated that they had assessed over 60% of their elderly patients in the first year (1990-91). A substantial proportion of assessments were estimated to have been conducted on an opportunistic basis and few practices were doing all the assessments of those aged 75 years and over in the patients' homes. In the majority of practices, the general practitioners and practice nurses were the only personnel carrying out assessments. Only 9% of the doctors and 34% of the nurses interviewed had been specially trained to carry out the assessment; 54% of nurses said they would like more training in this area. Both doctors and nurses reported that the assessments did detect previously unknown problems, although over half of doctors reported that they rarely picked up new mental health problems. Increased referrals to social services as a direct result of the assessments were reported by 63% of doctors. The majority of doctors and nurses reported that routine assessments were useful in providing advice and reassurance to elderly people. Two thirds of doctors said they would continue to offer at least selected groups of their elderly patients routine assessments, even if not contractually obliged to do so. CONCLUSION. The findings suggest that the experiences of the first two years of this activity had convinced some general practitioners that routine assessment of elderly patients is worthwhile. However the increased demand for other services must obviously be met by an increase in resources if the effectiveness of these assessments is not to be undermined.