Giant cell arteritis (arteritis temporalis) is the most common form of systemic vasculitis in the elderly. A series of symptoms such as new-onset headache, jaw claudication, proximal myalgia, weight loss, and fever may lead to the diagnosis. However, there is also a silent or occult presentation with minor or no systemic symptoms, especially no headache. A number of laboratory values (erythrocyte sedimentation rate, CRP, fibrinogen, thrombocytes, and cardiolipin antibodies) indicate giant cell arteritis, but none of this proves the diagnosis. Temporal artery biopsy is the gold standard for diagnosis of giant cell arteritis. Due to skip lesions, a negative result does not exclude the diagnosis. The most important complication of giant cell arteritis is visual loss in one or both eyes due to AION or retinal artery occlusion. Usually, visual loss is irreversible even with therapy. Corticosteroids are the drug of choice to treat giant cell arteritis. Therapy is required for a long time, monitored by parameters of inflammation (ESR, CRP).