There are few data on the disability caused by asthma in elderly subjects. The aim of this survey was to assess the functional status of a population aged 65 years or more, being treated for asthma-related symptoms. A representative sample of 3,777 elderly people, living at home in the South-West of France, was surveyed using a standardized questionnaire on factors of ageing and their consequences. To assess the functional status, five scales were used: Activities of Daily Living (ADL); Instrumental Activities of Daily Living (IADL); Rosow and Breslau scale; Mobility; and a Subjective Health Scale. Patients treated for asthma-related symptoms were identified by means of their use of the anti-asthma drugs mentioned in the questionnaire. In a second stage, the presence of asthma-related symptoms was further established by enquiring from their general practitioners and by direct questioning of the patients. Among 135 subjects taking anti-asthma drugs, 83 (61%) had positive responses to specific questions, either from their doctors or from themselves, allowing them to be identified as "asthmatic". In comparison with a control group matched for age and sex (n = 166; two controls for each patient), asthmatic patients had a higher dependence in the IADL scale, a greater self-assessment of poor health, and a greater handicap in mobility. However, they had the same level of ADL disability as controls. Despite adjustment for residential area, depressive symptoms, Mini Mental Status (MMS) Exam score, visual and auditory impairment, and joint pain, patients treated for asthma still had a higher risk of disability in daily life, and a poorer subjective health than controls.(ABSTRACT TRUNCATED AT 250 WORDS)