The centre-right Brazilian Social Democracy Party (PSDB) nominated José Serra, who resigned as Governor of São Paulo to mount his presidential campaign.

[6] For his vice presidential running mate, Serra chose Indio da Costa, a conservative Federal Deputy from Rio de Janeiro who was a member of the right-wing Democrats party.

[7][8] Marina Silva, a Senator from the northwestern state of Acre and former Minister of the Environment under Lula, left the PT to mount a candidacy as part of the Green Party.

Silva criticized the environmental policies of the Lula Administration and ran a campaign in support of sustainable development, ending corruption, and decriminalizing marijuana.

[9] Silva, who would've been the first Black woman to serve as President,[10] saw support from younger voters and managed to win almost 20% of the vote in the first round, well exceeding initial expectations.

[16] Influential members of the opposition during the Lula administration, such as Arthur Virgílio, Heráclito Fortes, Marco Maciel, and Tasso Jereissati, were not able to obtain re-election and will no longer serve in the National Congress.

[26] Two of Lula's key allies tipped as potential successors, former Minister of Finance Antonio Palocci and former presidential Chief of Staff José Dirceu, were harmed by their involvement in the 2005 Mensalão scandal.

[28] Former Mayor of São Paulo Marta Suplicy, who served at the helm of Brazil's largest city from 2001 to 2005, was considered to be, along with Dilma, the most likely candidate to lead the PT in the 2010 presidential election.

[35] Ciro Gomes, former governor of Ceará and Minister for National Integration during Lula's first cabinet, was a possible candidate for the Brazilian Socialist Party (PSB).

[36][27] Following the selection of Dilma as the candidate of the PT, the ruling centre-left group was worried that Ciro's bid could take votes from Rousseff,[20] and thus, on April 27, PSB declined to launch his candidacy in order to support her.

[37] Gomes, a populist who had appeared on third place in polls from May 2009 to April 2010, had been a presidential candidate in 1998 and 2002, when he had a poor result after making sexist remarks and struggling to control his temper.

[20] In addition to Dilma, Suplicy, and Gomes, other PT members or allies were mentioned as being potentially tapped by Lula to run in his absence.

[27] José Serra, the Governor of São Paulo, resigned from the position to mount a bid for the presidency as a member of the dominant centre-right Brazilian Social Democratic Party (PSDB).

[44] On June 30, 2010, Plínio de Arruda Sampaio, a longtime politician who was formerly a senior PT official, was chosen to serve as PSOL's presidential nominee at the 2010 convention.

As the media printed such news, the United Socialist Workers' Party announced that if this coalition was formed, it would launch the candidacy of its president José Maria de Almeida.

[45] However, a resolution approved by members of PSOL determined that the coalition would be formed if PV gave up its alliances with the Lula administration, PSDB, DEM, and neoliberal stances.

[44] Another faction of PV, led by Fernando Gabeira, is explicitly in favor of an alliance with PSDB, which left very few people in the party able to accept the proposal.

According to the Superior Electoral Court's guidelines, once the official campaign began the candidates are allowed to participate on marches, motorcades, and use sound trucks to ask for votes and distributing leaflets.

[49] Both candidates offered little threat to the economic stability of the country, but they differed significantly on issues such as fiscal discipline, foreign policy and state intervention.

[12] Rousseff, in the other hand, favors a bigger role for state enterprises in the economy, which could reduce participation by private firms in sectors such as banking, oil and gas.

[50] Rousseff was expected to continue Lula's foreign policy, boosting ties with developing nations, pushing for reform of multilateral bodies and lobbying for a permanent seat on the U.N. Security Council.

He argues that "while U.S. officials under both Bush and Obama have maintained a friendly posture toward Brazil, it is obvious that they deeply resent the changes in Brazilian foreign policy [...] and its independent stances with regard to the Middle East, Iran and elsewhere.

[53] Rousseff has defended the maintenance of the economic policies of the Lula government, but has also promised to hold a tax reform in order to alleviate the expenses of workers.

[53] Silva has proposed the creation of green jobs through tax incentives for environmentally friendly businesses, in order to reduce the emission and consumption of carbon dioxide.

[53] Silva defended the creation of a "new institutional structure for public safety", which would combine the police work with investments in preventive policies.

[54] According to the Superior Electoral Court's guidelines, the candidates whose parties are not represented in the lower chamber of the National Congress are not able to participate in televised debates.

[56] The electoral programs are considered a key campaign tool in Brazil, where TV and radio are the main sources of information for most voters.

[55] The free air time on radio and TV also includes candidates contesting races for Governors, Legislative Assemblies, and both houses of the Congress.

On October 20, after PSOL instructed its members to vote for either PT's Dilma Rousseff or blank/null in the second round,[64] Heloísa Helena decided to leave the presidency of the party.

[68] On October 14, the Progressive Party, a member of the Lulista[clarification needed] coalition bloc in the National Congress which had remained neutral in the first round, decided to support Dilma.