Electroencephalography (EEG) is a non-invasive method that records the brain signals with time resolution in the millisecond range, thereby allowing the monitoring of subjects’ mental states in real time. Using appropriate biomarkers extracted from these EEG signals and presenting them back in a neurofeedback loop can foster neural compensation mechanisms by teaching subjects to modulate their brain activity. Over the last decades, several neural biomarkers of aging have been described, with growing evidence suggesting that neuromodulation may have an important role in regulating brain activity in the elderly. Methods and objectives We used three neural biomarkers of aging, namely the Peak Alpha Frequency, the Gamma-band synchronization, and the Theta/Beta ratio, in the framework of an EEG-based brain-computer interface, with two main objectives: 1) to test whether healthy elderly people with subjective memory complaints may learn to modulate their brain activity through EEG-neurofeedback training in a double-blind, placebo-controlled study; and 2) whether that neuromodulation may have a positive impact on subjects’ cognition. Results A significant self-modulation of two neural biomarkers that usually decline with age was observed exclusively in the group of subjects who underwent the EEG-neurofeedback training, in clear contrast with the subjects who received the sham feedback. This neuromodulation did not have a direct effect on subjects’ cognitive abilities, as measured by neuropsychological tests pre-versus post-training, probably because all the subjects accurately performed these tests already at study entry (i.e., pre-training). Conclusion The results of this double-blind study are in line with one of the main criteria for successful neuromodulation, thus encouraging research on EEG-neurofeedback as a promising non-pharmacological intervention for promoting self-regulation of brain activity with a view to improve cognitive aging.