New, not yet widely known concepts pertaining to Gamma Knife (GK) radiosurgery for brain metastases are reviewed. In the author's experience, GK is a safe and effective treatment. Though lesion size is a limitation, high tumor control rates are possible when 1-4 lesions are irradiated with <or=20 Gy. Recurrence is rare in such cases, as are radiosurgical complications. Symptomatic complications, i.e. radionecrosis of normal brain tissues, are slightly more common in long-surviving patients. However, since most patients die of causes other than metastatic brain disease, i.e. before long-term complications manifest, good brain function is usually maintained till death. Factors predicting longer survival are youth, better performance status and absence of active nonbrain disease. Although some studies found retreatment for new lesions to be less frequent when whole brain radiotherapy (WBRT) is combined with surgery or GK radiosurgery, in our experience neither survival nor local recurrence rates improve significantly with WBRT. Advantages of GK over WBRT include brief hospitalization, higher control rates, better symptom palliation, all MRI-detected lesions can be treated, other treatments (e.g. radiotherapy) need not be postponed, irradiation can be repeated, the incidence of dementia (due to radionecrosis) is far lower and more tumors (30+) can be treated in one session. We advocate meticulous MRI follow-up to detect recurrence and assess tumor necrosis. All detectable tumors should be irradiated, so long as the patient wishes to continue treatment.