Background: The severe burden imposed by frailty and disability in old age is a major challenge for health-care systems in low- and middle-income countries alike. The current study aimed to provide estimates of the prevalence of frailty and disability in older adult populations and to examine their relationship with socioeconomic factors in six countries. Methods: Focusing on adults aged 50+ years, a frailty index was constructed as the proportion of deficits in 40 variables, and disability was assessed using the World Health Organization Disability Assessment Schedule (WHODAS 2.0), as part of the Study on global AGEing and adult health (SAGE) Wave 1 in China, Ghana, India, Mexico, Russia and South Africa. Results: This study included a total of 34,123 respondents. China had the lowest percentages of older adults with frailty (13.1%) and with disability (69.6%), whereas India had the highest percentages (55.5% and 93.3%, respectively). Both frailty and disability increased with age for all countries, and were more frequent in women, although the sex gap varied across countries. Lower levels of both frailty and disability were observed at higher levels of education and wealth. Both education and income were protective factors for frailty and disability in China, India and Russia, whereas only income was protective in Mexico, and only education in South Africa. Conclusions: Age-related frailty and disability are increasing concerns for older adult populations in low and middle-income countries. The results indicate that lower levels of frailty and disability can be achieved for older people, and the study highlights the need for targeted preventive approaches and support programs. (C) 2016 Elsevier Ireland Ltd. All rights reserved.