Despite his failure to make it to Victory Lane this season -- he will have one more chance on Saturday night -- Andretti became a more complete driver during the off-season and saw his work translate to better results on road and street courses.
Andretti has long been known as an oval ace over his nine seasons of competition but struggled on the road and street courses until he spent time in Europe honing his skills.
Now he will look forward to taking those improved skills to the next level and chase a championship in the No. 25 entry that will continue to be sponsored by the Dr. Pepper Snapple group.
"I feel we have been getting closer to a championship title and an Indy 500 win, and I wouldn't want to win it with anyone more with the Dr. Pepper Snapple family and with my dad," Marco said in a statement. "I feel like I have a lot of unfinished business and a lot of good results coming our way."
Andretti is the grandson of racing legend Mario Andretti and the son to Michael.
He carried the tradition in consistent fashion this season, ranking a career-best fifth in the championship standings, two poles and 14 top-10 finishes this season. While he hasn't won this season, his performance has dictated that he was capable of it and that's what the operation is banking on over the next two seasons.
While it makes a lot of sense for Andretti to stay with Andretti Autosport, the 26-year-old did shop his services around before settling down with the team that he has driven for since 2006. Next up for Andretti is to announce the rumored manufacturer switch from Chevrolet to Honda and to resign James Hinchcliffe, who has won three races this season.
Andretti has two wins in 132 career starts.