The progressive increase in population aging, specially evident in Spain, remark the importance to estimate the volume and the prevalence trends of dependency in the 65 years and over Spanish population. The dependency volume was calculated applying the 1993 and 1999 estimated prevalences in the longitudinal study "Aging in Leganes" to the Spanish population of 1991 and 2001. A random study sample of 1560 subjects 65 years was selected in 1993 in the city of Leganes (Madrid). Response rate at baseline was 82% (n = 1283). New information was collected in 1995 (n = 827), 1997 (n = 666) and 1999 (n = 475). Dependency was defined as needing help in at least one of eight Activities of Daily Living ADL. A multilevel model for repeated measures was fitted regressing ADL dependency on age, sex, education and survey year. There is a decline in ADL dependency by age in both, men and women. At advanced ages, this trend is reversed and there is an apparent increase in dependency. The prevalence is higher in women and in low educated subjects. The total number of ADL dependent people increased from 903,276 to 995,338 from 1991 to 2001 although the average age of dependent older people increased. Postponement of disability means longer healthy life expectancy and increasing volumes of very elderly disabled people, particularly women. Consequences for health, labour reform and social security systems can be very important.
