Background The aging population in Latin America is characterized by not optimal conditions for good health, experiencing high burden of comorbidity, which contribute to increase the frequency of frailty; thus, identification should be a priority, to classify patients at high risk to develop its negative consequences. Aim The objective of this analysis was to validate the FRAIL instrument to measure frailty in Mexican elderly population, from the database of the Mexican Health and Aging Study (MHAS). Materials and methods Prospective, population study in Mexico, that included subjects of 60 years and older who were evaluated for the variables of frailty during the year 2001 (first wave of the study). Frailty was measured with the five-item FRAIL scale (fatigue, resistance, ambulation, illnesses, and weight loss). The robust, pre-frail or intermediate, and the frail group were considered when they had zero, one, and at least two components, respectively. Mortality, hospitalizations, falls, and functional dependency were evaluated during 2003 (second wave of the study). Relative risk was calculated for each complications, as well as hazard ratio (for mortality) through Cox regression model and odds ratio with logistic regression (for the rest of the outcomes), adjusted for covariates. Results The state of frailty was independently associated with mortality, hospitalizations, functional dependency, and falls. The pre-frailty state was only independently associated with hospitalizations, functional dependency, and falls. Conclusions Frailty measured through the FRAIL scale, is associated with an increase in the rate of mortality, hospitalizations, dependency in activities of daily life, and falls.