Sampaoli's men were eliminated from the 2014 tournament on penalties by hosts Brazil in the last 16, but impressed in the group stage, beating holders Spain 2-0.
The 54-year-old had initially committed to the role until next year's Copa America, but has now said that he is prepared to stay until the next World Cup.
The Chilean professional football association (ANFP) confirmed the news in a statement on Tuesday.
The statement quotes Sampaoli as saying: "After meeting this morning with the President of ANFP and the FFCh (Chilean Football Federation), Mr Sergio Jadue, I wish to inform that I have taken the decision to remain in the position of technical director of the Chile national team and direct it to the 2015 Copa America in Chile, the Copa America's centenary in 2016 in the United States and the qualifiers for Russia 2018, including our participation in such a World Cup."
Argentinian Sampaoli took charge of the national team in 2012 following a successful stint as coach of Universidad de Chile.
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