Ability in activities of daily living (ADL), use of assistive devices, and relation to functional limitations and impairments were studied among persons between 70 and 76 years of age within the Inter-Vention study of Elderly in Göteborg (IVEG) Sweden. An ADL index was developed including instrumental activities (I-ADLs) (cleaning, shopping, transportation and cooking), which was combined with Katz' Index of personal daily life activities (P-ADLs) (bathing, dressing, going to the toilet, transfer, continence and feeding). Independence of and dependence on assistance from another person was assessed and it was possible to classify performance according to an ordinal scale of ADL-steps. The reliability and validity of the scale were tested in an out-patient sample (n = 85) as well as in a population of 76-year-olds (n = 659) and were found to be sufficient (coefficients of reproducibility and scalability, internal consistency, inter- observer reliability, content, construct, and criterion validity). The "Staircase of ADL" can be used for observation and documentation of different levels of ability/disability for individuals, groups and for population studies. Most persons (83%) were independent in all activities at age 70 (n = 617). Among survivors followed longitudinally, the incidence of disability was 8% between 70 and 73 and 26% between 73 and 76 years of age. Dependence at age 70 could predict mortality as well as institutionalization. No sex differences were found in the proportion with overall disability. Assistance given by relatives dominated both at 70, 73 and 76 years of age. One fifth at age 70 and almost half of the population at age 76 used assistive devices (AD) in daily life activities, and the use was more frequent in women (52%) than men (37%) at age 76 (n = 595). During the studied age interval, 39% "new users" were found, while 22% were "temporary users". The usage rate was high and the effectiveness of ADs increased the person's ability to master the situation, especially evident as increased safety and reduction of effort in activities of daily living, implying a reduced degree of handicap. Physical impairments and functional limitations had a considerable impact on dependence in daily life activities as persons dependent in ADL had lower maximal walking speed, grip strength, knee extensor strength, stair-climbing capacity and forward reach than those who were independent in ADL (n = 602). Walking speed in both women and men and sight impairment in men had the greatest influence on dependence in ADL. Women and men who stayed independent over the period (70-76) had significantly higher maximal walking speed and knee extensor strength at the age of 70 than those who became dependent or were dependent on both occasions.