A 24-year-old male patient was treated with Gamma Knife surgery (GKS) for medial temporal lobe epilepsy. The treatment parameters were in accordance with established practice. Epilepsy stopped after 2 years and medication was discontinued. Four years later, he developed a profound radionecrosis leading to blindness. As had refused surgical intervention his blindness has become permanent. As this is the second such case to be reported, it is considered a cause for concern, since microsurgery remains a safe alternative treatment. It is suggested that GKS for mesial temporal lobe epilepsy should be restricted to University centres of excellence as part of research projects under the control of ethics committees. It should not at present be considered to be a safe treatment for general use.