The mining giant reported net profit of $US5.8bn for calendar year 2011, compared to $US14.32bn for 2010.
Rio Tinto said the result was primarily due to an impairment charge of $US8.9bn related to its aluminium business.
Rio Tinto also reported record underlying earnings before interest, tax, depreciation and amortisation of $US28.5bn, up 10% on 2010.
Cash flows from operations also broke records, up 16%.
However, chief executive Tom Albanese said he felt it was right not to be considered for an annual bonus for 2011, given the acquisition of the Alcan aluminium unit happened on his watch.
Rio bought the Alcan aluminum business for $US38 billion at the height of the boom in 2007.
Mr Albanese maintained that growth in demand for aluminium remained strong and the company was working hard to improve the performance of its aluminium business.