Mohamed Ould Abdel Aziz, who led the 2008 coup d'état, won a narrow first-round majority in the election, according to official results.
Following the coup which deposed President Sidi Ould Cheikh Abdallahi on 6 August 2008, the new junta (the High Council of State) promised that a presidential election would be held "as soon as possible".
On 4 February 2009, while still expressing support for the coup and saying that Abdallahi should not be restored to the Presidency, Ahmed Ould Daddah—the country's main opposition leader, who heads the Rally of Democratic Forces (RFD) and placed second in the 2007 presidential election—proposed that the army give up power and that anyone who was serving in the military at the time of the coup should not be allowed to run in the presidential election.
[6] Abdel Aziz announced that he would run in the election on 29 March 2009, as was widely expected, and said that he would resign as Head of State (to be succeeded by the President of the Senate) in order to stand as a candidate.
He also said that the election would be held as planned on 6 June, contradicting rumors of a delay that could facilitate possible mediation aimed at securing the participation of opposition parties.
Boulkheir denounced the "unilateral electoral agenda of the putschists" and warned that "neither tanks, nor guns nor live bullets can stop our fight against the usurpation of power by force".
[12] The deadline for the registration of presidential candidacies expired on 22 April; by that point none of the major opposition leaders, including RFD President Daddah, had registered, as they were all participating in the boycott.
[3] The Constitutional Court approved four candidacies on 27 April: those of Abdel Aziz, Ibrahima Sarr, Kane Hamidou Baba, and Sghair Ould M'Bareck.
[20] Ely Ould Mohamed Vall, who headed the 2005–2007 military junta, announced on 6 June 2009 that he would be a presidential candidate, running as an independent.
He stressed, however, that his candidacy was not directed against any particular individual, and he said that his goal, if elected, was "to build a reconciled country that is politically and economically viable and stable".
[22] The moderate Islamist National Rally for Reform and Development (RNRD), which opposed the coup and participated in the FNDD, designated its President, Mohamed Jemil Ould Mansour, as its candidate on 14 June.
[26] Abdel Aziz, also stressing the importance of change, presented himself as a champion of the poor;[26][27] he had substantially lowered the prices of basic goods and services, engaged in public works projects, and granted land rights.
The New York Times reported that support for Abdel Aziz in Dar Naim, a "desperately poor" Nouakchott neighborhood, was "universal".
Meanwhile, FNDD spokesman Mohamed Ould Mouloud alleged "massive fraud"; he said that the coalition would gather evidence and take the matter to the Constitutional Court.
[27] Partial results on 19 July, with 61.17% of votes counted, showed Abdel Aziz with a narrow first-round majority of 52.2%; his supporters celebrated in the streets of Nouakchott.
Daddah then called for "a recount of the votes and a chemical analysis of the ballot papers", while urging the people "to reject this new coup d'etat" and "use all forms of democratic struggle".
[45] Abdel Aziz was sworn in at a ceremony in Nouakchott on 5 August 2009, one day prior to the first anniversary of the coup that initially brought him to power.