Thyroid-associated ophthalmopathy is a local autoimmune reaction in the orbit. Typical signs are retraction of the eyelid, periorbital oedema, proptosis and impaired eye motility. Exposure keratopathy or compression of the optic nerve may be a complication. Patients with severe proptosis or progressive loss of vision need an efficient and safe treatment modality. Immunosuppression may be the first choice, followed by surgical decompression of the orbit. We describe a combined external and endoscopic approach with resection of the lateral, inferior and medial orbital walls. In this way, the increased intraorbital pressure is relieved. Retraction of the upper eyelid is corrected by transconjunctival approach and the release of muscles from the tarsus.