Physical exercise is a very promising non-pharmacological approach to prevent or reduce the cognitive decline that occurs in people aged 60 years or older. The objective of this study was to determine the effect of a high-intensity intervallic functional training (HIFT) program on cognitive functions in an elderly Colombian population with mild cognitive impairment. A controlled clinical trial was developed with a sample of 132 men and women aged >65 years, linked to geriatric care institutions, which were systematically blind randomized. The intervention group (IG) received a 3-month HIFT program (n= 64) and the control group (CG) (n= 68) received general physical activity recommendations and practiced manual activities. The outcome variables addressed cognition (MoCA), attention (TMTA), executive functions (TMTB), verbal fluency (VFAT test), processing speed (Digit Symbol Substitution Test-DSST), selective attention and concentration (d2 test). After the analysis, improvement was found in the IG with significant differences with respect to the CG in the level of cognitive impairment (MoCA), attention (TMTA), verbal fluency and concentration (p< 0.001). Executive functions (TMTB) showed differences in both groups, being slightly higher in the IG (p= 0.037). However, no statistically significant results were found for selective attention (p= 0.55) or processing speed (p= 0.24). The multiple analysis of covariance (MANCOVA) showed the influence of the education level on all cognition assessments (p= 0.026); when adjusting for sociodemographic variables, the influence of the intervention remained significant (p< 0.001). This study empirically validates that the implementation of a HIFT program has a positive effect on cognitive functions in elderly people with mild cognitive impairment. Therefore, professionals specialized in the care of this population could consider including functional training programs as an essential part of their therapeutic approaches. The distinctive features of this program, such as its emphasis on functional training and high intensity, appear to be relevant for stimulating cognitive health in the geriatric population.