The 33-year-old Briton has signed a new contract with the German manufacturer that lasts until the end of 2020.
Hamilton will earn at least £30m a year, rising to a maximum of £40m, depending on bonuses.
Hamilton said a new contract had been “a formality” since he sat down with Mercedes F1 boss Toto Wolff to begin discussions last winter.
Lewis Hamilton has revealed that a Formula One team other than Mercedes approached him about a 2019 contract, but he insists he did not take the offer seriously.
Ferrari and Red Bull were the only other viable options for Hamilton given the gulf in performance between the top three and the midfield, and he revealed that one team attempted to open negotiations with him.
Mercedes have dominated F1 since the introduction of turbo hybrid engines in 2014, winning four consecutive drivers’ and constructors’ championship doubles.
Hamilton has won three of those titles, with the fourth going to former team-mate Nico Rosberg, who retired after becoming champion in 2016.
Hamilton’s first world title came with McLaren, using Mercedes engines, in 2008.