The 32-year-old, who also threatened to retire from international football in September 2012 before changing his mind, told team-mates in the dressing room after Sunday's 1-0 home win over Libya that he was ending his 16-year career with the Indomitable Lions, according to French newspaper L'Equipe.
His announcement follows a week of tension in the team camp after Eto'o demanded the selection of goalkeeper Carlos Kameni and striker Achille Webo against Libya, with German Finke refusing to agree.
Eto'o, four times African Footballer of the Year, initially suggested he was not fit to play because of a groin injury but did take part in the match and even wore the captain's armband before being replaced on the hour mark.
Cameroon now face a two-legged playoff in October and November to qualify for Brazil.
Eto'o, who signed for Chelsea from Russian side Anzhi Makhachkala last month, has scored 56 goals in 114 appearances for Cameroon and appeared at three World Cup finals in 1998, 2002 and 2010.
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