Primary vertex reconstruction at the ATLAS experiment

These proceedings present the method and performance of primary vertexreconstruction at the ATLAS experiment during Runs 1 and 2 at the LHC. The studies presentedfocus on data taken during 2012 at a centre-of-mass energy of √s = 8 TeV, and during 2015-2016at √s = 13 TeV. Some predictions toward future runs are also presented. The measurement ofthe position and size of the luminous region and its use as a constraint to improve the primaryvertex resolution are discussed.