Peru have been without a boss since Bengoechea left his role at the end of 2014, but, with a friendly against Venezuela on March 31, Gareca has stepped into the role.
The former Argentina international – who has managed across South America during his career – will look to build on their five wins in the last seven matches during 2014 ahead the Copa America in June.
"I thank Juan Carlos [Oblitas, Peru Football Federation sporting director] because they trusted me with this role. It is an honour. I am very happy. It is the biggest challenge of my life," the 57-year-old said.
"Being in charge of a country that I love, which has treated me very well and where I had the opportunity to learn, is a huge responsibility.
"I accept this challenge, knowing that we expect a tough, complicated but not impossible task. Nothing is impossible when you believe.
"I believe in Peru's football team."
