Objective: determine the extent to which each criterion of the frailty phenotype (either alone or grouped) contributes to the emergence of the syndrome in older people. Methods: observational and analytical study was conducted with 219 male and female older people in outpatient care. The evaluation of frailty syndrome was based on the phenotype proposed by Fried et al., the criteria of which are unintentional weight loss, self-reported fatigue, low grip strength, insufficient physical activity and slow gait. Multinomial logistic regression analysis was employed to evaluate the influence of each criterion of the phenotype alone or grouped. Results: a total of 219 individuals participated in the study. The most common frailty criterion was slowness in both frail and pre-frail individuals. Pre-frail individuals with slow gait were 9.42-fold more likely to become frail (OR = 9.42, 95%CI: 7.27-13.40, p = 0.001). The model with all five criteria explained 99.5% of frailty in the sample. Conclusion: slow gait was the most frequent frailty criterion in frail and pre-frail individuals. Therefore, this criterion seems to be the best predictor of frailty in older people and warrants close observation on the part of healthcare providers.