An Anglicized version of the SF-36, a recently developed generic health status measure, was tested among people aged 65 years and over in hospital outpatient and general practice settings as both a self-completed and interview-administered instrument. The SF-36 was quick to complete, with 84% completed in 10 minutes or less (median time 8 minutes), while the distribution of scores provided further evidence of its sensitivity and validity. As an interview-administered instrument the SF-36 was acceptable among all age groups, although 32% of outpatients and 10% of general-practice patients, consisting predominantly of people aged 75 years and over with poor physical or mental health scores, felt unable to self-complete the questionnaire. In addition, 26% of respondents missed out at least one of the 36 statements, with missing items being significantly related to older age and self-completion. Missing responses were mainly concentrated on a small number of questions whose emphasis on work or vigorous activities meant that they were frequently regarded as not applicable by elderly people. Suggested modifications to these questions for elderly respondents are given. With these changes the SF-36 is regarded as suitable for use as a self-completed questionnaire among the younger age group of elderly people, although some assistance may often be required by people aged 75 years and over and especially those with poor physical or mental health.