Background/Purpose: People are living longer. However, the aging process, coupled with lifestyle and health conditions, may lead to what is known as frailty syndrome. There is a consensus among researchers in the field that frailty is associated with adverse health outcomes, such as functional decline, dependency, recurrent falls, fractures, institutionalization, hospitalization and death. The aim of the present study was to analyze the relationship between frailty and mortality in a population of older people living in a Brazilian community. Methods: A prospective cohort study was conducted through two assessments in the city of Ribeirão Preto, state of São Paulo, with a mean follow-up period of 5.6 years. The sample was made up of 515 (75.37±7.28) older adults who were assessed in 2007/2008, and 262 (79.31±6.34) who were assessed in 2013. Data were analyzed using the Statistical Package for the Social Sciences (SPSS) 22.0; the Wilcoxon test, Cox regression and Kaplan-Meier survival analysis were also used. Results: We verified that most older people were considered non-frail in 2007/2008 (59.5%); 22.9% were identified as apparently vulnerable, and 17.6% were frail. In 2013, 28.7% were considered non-frail, 20.9% apparently vulnerable; and 50.4% were frail (an increase of 186%). A total of 24.7% died during the follow-up period; 45.7% were considered frail according to the Edmonton Frail Scale. The survival analysis showed that frail older people were more likely to die. Conclusion: Frailty developed during the period under study, in association with mortality: a greater proportion of non-frail older people were among the survivors. In the present study, frailty was considered an important predictor of mortality.