The 40-year-old former Monaco, Inter and Marseille midfielder succeeds Francois Zahoui a day after the Ivorian led the Elephants to defeat Mali 2-1 in a preparatory friendly match played in France.
Lamouchi was surprisingly preferred to more experienced candidates such as former England coach Sven Goran Eriksson, former Senegal coach Bruno Metsu and former PSG manager Antoine Kombouare.
Details of Lamouchi’s contract were not revealed by the Ivorian football body but he will likely lead the team through the qualifying campaigns of the 2014 World Cup and 2013 Africa Cup of Nations.
The Frenchman, who retired from football in 2001, is taking up his first coaching job with a national team.
Ivory Coast will begin their World Cup qualifying on June 2 against Tanzania, followed by a meeting with Morocco on June 9.