Giant cell arteritis (GCA, Horton's disease) is a subacute vasculitis of large-size arteries. GCA affects individuals above 50 years and its frequency increases with age. The key elements for diagnosis are clinical presentation, elevated inflammatory markers, imaging, and histology. Temporal artery biopsy is the gold standard for confirming GCA, but is gradually being replaced by non-invasive imaging techniques such as Doppler ultrasound and positron emission tomography. While corticosteroids remain the cornerstone of treatment, new therapies are helping to reduce their dosage and duration of use. In this review, the key aspects of diagnosing and treating GCA, based on the latest recommendations are discussed in this article.