AbstractWhereas high‐level evidence exists on chronic neuromodulatory effects of different brain stimulation approaches in reducing seizure frequency, evidence for acute antiseizure effects of electrical brain stimulation during seizures is sparse. As part of an ongoing trial, we implanted a patient with a novel focal cortex stimulation (FCS) device with a Laplacian electrode placed over a precentral focal cortical dysplasia. The baseline seizure frequency was 125 per month, consisting of (i) focal aware sensory seizures that invariably progressed to uni‐ or bilateral tonic contraction and clonic jerking, and (ii) primary motor seizures. Besides an overall reduction in seizure frequency, on‐demand stimulation had an immediate effect on seizures with a sensory phase, whereby 63%‐86% of these seizures were terminated by ictal stimulation. These observations provide the first evidence that ictal self‐triggered transcranial focal cortex stimulation can significantly interfere with the progression of seizure semiology.