INTRODUCTION: Frailty predicts functional decline and could be associated with adverse outcomes such as disability, multiple hospitalizations, falls, loss of mobility, and cardiovascular disease. In Colombia 12.5% of prevalence has been reported. In the present study, the different clinical variables associated with frailty were evaluated in a population of hospitalized patients older than 65 years in Bucaramanga, Colombia, in order to predict the behavior of these variables to generate measurement tools of greater applicability than that of currently existing tools. METHODS: An analytical observational cross-sectional study with nonprobabilistic sampling was conducted from January 2016 to June 2017 in patients older than 65 years of follow-up > 48 hours by the internal medicine service. Fried criteria were used to evaluate patients on their last day of hospitalization. RESULTS: A total of 155 patients were included, of whom 60.6% were frail. A combined analysis of the variables that showed association with frailty revealed that a calf circumference lower than or equal to 31 cm, a gait speed lower than or equal to 0.8 m/s, and age above 75 years were associated with frailty. It was also shown that being male and having a BMI > 27 kg/m2 are protective factors for frailty. CONCLUSIONS: The prevalence of frailty in hospitalized older adults was higher than that reported in local studies for the community population. According to multivariate analysis, the variables, when analyzed together, have a predictive ability of 92% to estimate frailty in hospitalized patients.