Introduction: Radionecrosis (RN) represents the main complication of stereotactic radiotherapy (SRT) for brain metastases. It may be observed in up to 34% of cases at 24 months after treatment and associated with significant morbidity in 10-17%. Areas covered: Our aim is to discuss the results of original studies on RN related to SRT for brain metastases. Expert commentary: Although the development of RN is unpredictable, larger volume of the lesion, prior whole brain irradiation, and higher dose of radiation represent the major risk factors. RN appears on MRI as contrast-enhancing necrotic lesions, surrounded by edema, occurring at least 3 months after SRT, localized within fields of irradiation. No firm criteria are established. Surgery can provide symptomatic relief but is associated with a risk of complications. Corticosteroids are considered the standard of care treatment, despite limited efficacy and many adverse effects. Bevacizumab represents another interesting option that needs to be validated.