The authors report a case of a human-habituated mountain gorilla, Alvila, resident at the San Diego Zoo, who was found to have a herniated intervertebral lumbar disc after being attacked by the gorilla troop's silverback male gorilla. Ultimately, the gorilla required surgical intervention for her disease and made a full recovery. To our knowledge, this is the only known case of spine surgery. A 36-year-old female human-habituated mountain gorilla (Gorilla beringei beringei), resident at the San Diego Zoo, was noticed by caregivers to walk with a substantial limp after being attacked by the gorilla troop's silverback male gorilla. Magnetic resonance (MR) imaging of her lumbar spine revealed a large herniated disk at the L1-2 level on the right. This finding appeared to correlate well with the gorilla's symptoms. The gorilla underwent a lumbar diskectomy under loupe. Post-operatively the gorilla did very well. The right leg weakness was immediately improved post-operatively. The gorilla continued to "crutch walk" initially, swinging on the upper extremities and not bearing weight on the lowers. However, by 2 weeks the limp was no longer noticeable to the zoo caregivers. The wound healed well and there was no evidence of wound infection or CSF leak. The gorilla was reunited with her troop and has reintegrated well socially. With 10 months of follow-up, the gorilla continues to do well. This is the only known case of spine surgery in a gorilla. For best surgical results, one needs to consider the similarities and differences between the gorilla and human vertebral anatomy. We believe that careful pre-operative planning contributed to the good early post-operative result. Ultimate assessment of the long-term outcome will require additional follow-up.