General elections were held in Mexico on Sunday, 2 July 2006. Voters went to the polls to elect a new President of the Republic to serve a six-year term, replacing then President Vicente Fox (ineligible for re-election under the 1917 Constitution); 500 members of the Chamber of Deputies (300 by the first-past-the-post system and 200 by proportional representation) to serve for three-year terms; and 128 members of the Senate (three per state by limited voting and 32 by proportional representation from national party lists) to serve for six-year terms.

Several local ballots were also held on the same day, including the head and legislature of the federal district, governors of Guanajuato, Jalisco and Morelos and local councillors in several states.

Due to controversial events in Mexican politics in the years preceding the election, the negative and aggressive tone of the presidential campaign, the personal interference of President Vicente Fox to favor the candidate of his party the National Action Party of Felipe Calderón, as well as the controversial and extremely close results that gave Calderón a lead of 0.6% of the vote (or 243,934 votes) over his rival Andrés Manuel López Obrador, member of the Party of the Democratic Revolution (who subsequently refused to recognize the results and claimed that the election had been rigged against him), Mexico went through a political crisis for the remainder of the year, as López Obrador called for protests throughout the country and proclaimed himself to be the "Legitimate President", while legislators of his party protested the inauguration of Felipe Calderón as President on 1 December. At the same time, the southern state of Oaxaca was marked by severe civil unrest during 2006 after a teachers' strike was violently repressed by Governor Ulises Ruiz Ortiz, which led to protests calling for his resignation; the 2 July elections in many regions of that state were disturbed by the ongoing conflict.

Although there were nationwide protests by López Obrador's supporters calling for a complete recount of the votes, this was rejected by the Federal Electoral Tribunal, which only authorized a recount in less than 10% of the polling stations and later concluded that the irregularities in the election hadn't been grave enough to change the outcome of the election. On 5 September, Calderón was officially declared by the Tribunal as the winner of the election.

Analysts agree that Calderón's launch of the Mexican drug war on 11 December (only ten days after taking office as President) was an extraordinary step to gain popular support and to cement his legitimacy in the aftermath of the convoluted elections and the subsequent crisis.

There were five registered candidates for the 2006 presidential election:

A non-registered candidate, Víctor González Torres (nicknamed "Dr. Simi" after the mascot of his national drugstore franchise) made a massive marketing campaign to enter the election, in spite of not being registered as an official candidate, and ran as a write-in candidate. His popular slogan was "The same only cheaper", but his campaign slogan was "To serve God and the people of Mexico". Ironically, he frequently stressed the fact that he paid all of his own campaign expenses, thus being the "cheapest" candidate. He was not considered a formal candidate but many press sources still publish his sayings and complaints against IFE, while some sources consider him a sort of "comic relief".

As of January 2005 only three candidates had made a public declaration of assets, liabilities and annual expenses. These figures were given in pesos, the total value of assets of each candidate follows at an exchange rate of 10.62 pesos to one United States dollar.