||Transitions between disability states in older people occur frequently. This study investigated predictors of disability transitions in the oldest old and was performed in the Leiden 85-plus study, a population-based prospective cohort study among 597 participants aged 85 years. At baseline (age 85 years), data on sociodemographic characteristics and chronic diseases were obtained. Disabilities in basic activities of daily living (BADL) and instrumental activities of daily living (IADL) were measured annually for 5 years with the Groningen Activities Restriction Scale (GARS). Mortality data were obtained. A statistical multi-state model was used to assess the risks of transitions between no disabilities, IADL disability, BADL disability, and death. At baseline, 299 participants (50.0 %) were disabled in IADL only, and 155 participants (26.0 %) were disabled in both BADL and IADL. During 5-year follow-up, 374 participants (62.6 %) made >1 transition between disability states, mostly deterioration in disability. Males had a lower risk of deterioration [hazard ratio (HR), 0.75 (95 % CI, 0.58-0.96)] compared to females. No gender differences were observed for improvement [HR, 0.64 (95 % CI, 0.37-1.11)]. Participants with depressive symptoms were less likely to improve [HR, 0.50 (95 % CI, 0.28-0.87)]. Participants with depressive symptoms [HR, 1.46 (95 % CI, 1.12-1.91)], >1 chronic disease [HR, 1.60 (95 % CI, 1.27-2.01)], and with cognitive impairment [HR, 1.60 (95 % CI, 1.20-2.13)] had the highest risk of deteriorating. Disability is a dynamic process in the oldest old. Deterioration is more common than improvement. Older men are less likely to deteriorate than women. The presence of depressive symptoms, chronic disease, and cognitive impairment predicts deterioration.