<p>Cognitive decline in older adults has significant implications for autonomy and quality of life. This study evaluated the combined effects of cognitive training (CT) and transcranial direct current stimulation (tDCS) on cognitive performance in older adults. Two CT approaches—core training and strategy training—were paired with either active or sham anodal tDCS over the left DLPFC. Eighty-five participants were assigned to three groups: (1) CT with active tDCS, (2) CT with sham tDCS, and (3) a control group attending memory-related lectures. Participants underwent 16 intervention sessions and completed cognitive assessments at three points: pre-intervention, immediately after, and three months post-intervention. Results showed that the active tDCS group experienced immediate and sustained improvements across all cognitive tests, while the sham tDCS group showed gains only in specific memory tasks. The control group showed no significant changes. These findings suggest that combining CT with active tDCS is more effective in enhancing and sustaining cognitive performance in older adults compared to CT alone. The study highlights the importance of further research to explore the mechanisms underlying the effectiveness of combined CT and tDCS interventions and their potential in mitigating age-related cognitive decline.</p><p><i>Trial registration</i>: NCT04997226. 09/08/2021.</p>