RÉSUMÉ
INTRODUCTION: The sarcopenia is a negative aspect for the health of the elderly, increased the risk for disease and mortality. Additionally can contributes greatly to functional reducing capacity and quality of life. OBJECTIVE: To identify the prevalence and factors associated with sarcopenia in institutionalized elderly. METHODS: This is a cross-sectional study, conducted with 216 elderly people, aged ≥ 60 years, of both sexes, residents in long-term care facilities in Salvador-Bahia, Brazil. To identify sarcopenia was used the skeletal muscle Index. Covariates were considered: gender, age, time of institutionalization, type of institution, body mass index and functional capacity. The Association between sarcopenia and covariates was evaluated using the Poisson regression model with robust variance. RESULTS: The prevalence of sarcopenia in the elderly was 72.2% and this condition was associated with male sex (PR = 1,33; CI 95% = 1,081,65), thinness (PR = 1,29; CI 95% = 1,16-1,43) and obesity (PR = 0,37; CI 95% = 0,23-0,61). CONCLUSION: The prevalence of sarcopenia was high among the elderly living in long-term institutions, especially among men. Elderly with thinness showed greater impairment of muscle reserves, while the state of obesity was protective.