BHP conducted an audit tendering process during the year in the wake of regulations forcing firms to rotate their statutory accountants. As a result, incumbent KPMG did not bid to continue its role.
EY will take over from 1 July 2019, meaning rival KPMG will audit BHP's 2017, 2018 and 2019 sets of accounts.
Read more: BHP Billiton commits to US shale exit
Hywel Ball, EY’s UK head of audit, said: “We are thrilled to be named auditors to BHP Billiton and are proud to have been selected from among the competition.
BHP is the largest diversified miner in the world. Our global structure, combined with our wealth of experience in the sector, helps enable us to advise international businesses of this scale. We are delighted about the opportunities this audit win will bring to our people across the globe.
Last month, EY picked up Tate and Lyle as audit clients.
EU regulations and the UK Competition and Markets Authority rules required BHP to have a new external auditor in place by 1 July 2023.