Objectives: to describe the effect of photobiomodulation therapy in the treatment of post-herpetic neuralgia in the elderly. Case report: a female patient, 61 years old, 56 kg, 1.67cm tall, sought treatment at the Laser Therapy Center of the Universidade do Vale do Paraíba, in the city of São José dos Campos, São Paulo, Brazil, on October 27, 2015. She had been diagnosed with herpes zoster on September 4, 2015 with complaints of intermittent neuralgia in the long thoracic nerve path and spikes of intense pain (level 10, according to the analogue pain scale). Photobiomodulation was performed with low intensity laser spot irradiations at 20 points around the herpesvirus nerve, with a distance of 2cm between each point. Irradiation was performed at each point after 20 seconds, with 3J/cm2 per point and total energy of 60 J. At the end of the treatment the pain level was 0 and the patient exhibited a normal sleep pattern (8 hours of sleep). Conclusions: Photobiomodulation treated painful discomfort, improved the quality of life of the patient and proved to be an effective, safe and promising treatment, with significant potential to become the therapy of choice in such cases.