The 46-year-old replaces Felipe Calderon, who has ruled the country for 12 years of an interregnum for the Institutional Revolutionary Party which has governed Mexico for 71 years.
One of the key tasks for Nieto will be to handle the drug cartels that have caused 50,000 deaths in last six years.
Nieto has held a variety of posts in the Mexican government in the last decade including a state governorship. He won the presidential election in July with 38.21 percent of the vote.
Mexico City: Enrique Pena Nieto was sworn in Saturday as Mexico's new president, prior to his ceremonial inauguration.
First Published: Saturday, December 01, 2012, 19:27