Objective: To investigate the factors related to low social participation in older adults. Method: A hierarchical model was drawn using data from 2,251 participants of the Fibra study, aged 65 years or more, without cognitive impairment suggestive of dementia, who were living in seven Brazilian cities. Older adults with those conditions have higher odds to be less socially engaged than their counterparts. Conclusion: Personal conditions, such as socioeconomic and health status were predictors of low social participation in older adults. Initiatives aiming at active aging promotion should focus primarily on vulnerable elderly, especially those with health and/or social disadvantages.Keywords: health of the elderly; aging; social behavior; socioeconomic factors; social support.