With increasing life expectancy and rapid ageing, there is an expanding number of older people who have functional declines, greater needs for care and support and who are at increased risk of insufficient social interaction. Longitudinal investigations on the interplay between loneliness, social isolation and care dependence remain limited. This study thus aimed to investigate the longitudinal reciprocal association between social isolation/loneliness and care dependence among older adults in Latin America and China. We analysed data from the population-based cohorts from the 10/66 Dementia Research Group (DRG) project (baseline 2003-07 and follow-up 2007-2010). The 10/66 DRG study recruited and followed up older adults aged 65years or above in 11 catchment areas in Latin America and China. A total of 15,027 older adults from Latin America and China (mean age=73.5, standard deviation=6.5) were included in our analyses. Cross-lagged panel models were used to investigate potential reciprocal associations. Loneliness was positively associated with care dependence at baseline (β=0.11, p<0.001 in Latin America; β=0.16, p<0.05 in China]. Social isolation consistently had a stronger positive association with care dependence across all study sites in both waves. Longitudinally, care dependence positively predicted loneliness (β=0.10, p<0.001) and social isolation (β=0.05, p<0.001) in Latin American study sites but not in China. Yet there was no statistical evidence of lagged effects of loneliness and social isolation on care dependence in all study countries. Older people with care dependence are at risk of developing loneliness and social isolation. It is crucial to develop complex care models using a societal approach to address social and care needs holistically, especially for the older group with declining functional capacity. Future longitudinal research is required to explore the causal mechanisms of relationships and cultural differences, in order to inform the development of culturally appropriate care models.