OBJECTIVES:In China, few studies reported the disability situation and the association between disabilities with chronic conditions in aged people. This study investigates the cross-sectional trends of prevalence and severity of activities of daily living disability (ADL) in Chinese oldest-old people from 1998 to 2008, and identified the potential risk factors of disability. DESIGN:A combination of population-based longitudinal prospective study and probabilistically sampling cross-sectional studies. SETTING:The Chinese Longitudinal Healthy Longevity Survey (CLHLS) was based on a random sampling of aged people from twenty-two provinces in China. PARTICIPANTS:A total of 52,667 participants aged from 80 years old to 105 years old sampled in the year of 1998 (n=8,768), 2000 (n=10,940), 2002 (n=10,905), 2005 (n=10,396) and 2008 (n=11,658) were analyzed respectively. RESULTS:The prevalence of ADL disability decreased from the year of 1998 (18%) to 2008 (12%). The disability prevalence significantly increased in 2002 and decreased in 2008 (P<0.001) in total participants than the year of 1998. The prevalence trends of low ADL disability level were almost identical with that of the total ADL disability. Stroke/cerebrovascular disease (CVD) and cognitive impairment were the strongest risk factors of disability. Vision impairment became less associated with ADL disability (P=0.045), while the association between multimorbidity and ADL disability became stronger (P=0.033). CONCLUSIONS:The prevalence of ADL disability declined among the oldest-old population in China from the year of 1998 to 2008 without obeying a linear pattern. Temporal trends of ADL disability mainly attributed to the change of low disability level prevalence. Stroke/CVD and cognitive impairment were the most common risk factors of disability. Vision impairment caused disability has become less common, while risks of multimorbidity related disability increased.