Optic nerve decompression is a procedure that is now receiving increasing clinical attention. However, there are currently no standardized treatment protocols in the therapy of traumatic or pressure insults to the nerve. The present retrospective study was designed to report our experience with microscopic endonasal transethmoid-sphenoid optic nerve decompression in 24 unilateral trauma cases and 11 unilateral skull base tumor patients. In general preoperative visual acuities in the trauma patients were worse than in the tumor patients. Following surgery, 9 of 11 tumor patients (82%) had at least some improvement of their vision, including 5 complete recoveries. In the group with traumatic visual impairment, 16 of the patients had no light perception preoperatively. Postoperatively, 13 patients (54%) had at least some improvement, with 4 patients regaining normal or near normal vision. Compared to other techniques and approaches, our technique is a minimally invasive procedure for optic nerve decompression, reducing unnecessary operative trauma to nasal structures, skin incisions or even craniotomy and frontal lobe retraction.