Background. Despite the availability of various options for movement restoration in stroke patients, there is no effective treatment for patients who show little or no functional recovery of upper limb motor function. Objective. The present study explored the feasibility of real-time functional magnetic resonance imaging brain–computer interface (fMRI-BCI) as a new tool for rehabilitation of this patient population. Methods. Healthy adults and chronic subcortical stroke patients with residual movement were trained for 3 days to regulate the blood oxygenation level dependent (BOLD) response in the ventral premotor cortex (PMv), a secondary motor area with extensive anatomic connections with the primary motor cortex. Effect of learned modulation of the PMv was evaluated with BOLD signal changes across training sessions, transcranial magnetic stimulation (TMS), and a visuomotor task. Results. fMRI-BCI feedback training showed learning with a significantly increasing BOLD signal in the PMv over sessions. Participants’ capability to learn self-regulation was found to depend linearly on intracortical facilitation and correlated negatively with intracortical inhibition measured by TMS prior to feedback training. After training, intracortical inhibition decreased significantly with the volitional increase of the BOLD response in the PMv, indicating a beneficial effect of self-regulation training on motor cortical output. Conclusion. The study provides first evidence for the therapeutic potential of fMRI-BCI in stroke rehabilitation.