Large-vessel vasculitis (LVV) is a rare set of diseases that mainly affect the aorta and its primary branches. The most common of the diseases are giant cell arteritis (GCA) and Takayasu arteritis (TA). Mainly because of the rarity of these diseases, there is no standardized protocol on how to monitor patients, when to repeat arterial imaging, or when to change therapy. This situation leads to significant variations in clinical practice. In the last 5 years, the Outcome Measures in Rheumatology (OMERACT) Vasculitis Working Group has been developing a core set of domains in LVV. The working group recognizes the need to obtain final endorsement of the domains prior to selecting and/or developing associated outcome measurement instruments.