Tony Tan
On 1 July 2011, President S. R. Nathan announced his retirement while his second term drew towards a close. Initially, he did not rule out a third term.

Breaking tradition from previous Presidential Elections, especially the last two that ended in walkovers, this turned out to be a stiff multi-corner contest with four candidates receiving the Certificate of Eligibility from the Presidential Elections Committee. Three were once members of the ruling PAP, serving at the different levels of ministerial, backbench and grassroots respectively, and the last stood as a SDP candidate in the General Election four months earlier. Coincidentally, all of them had the surname "Tan" and were dubbed the "Tan Quartet".

Former Deputy Prime Minister Dr Tony Tan, who resigned as chairman of Singapore Press Holdings and posts in the Government Investment Corporation to contest, was backed by the outgoing President, several PAP ministers, associations and unions. Hence, he was perceived to be the PAP government's endorsed candidate despite flashing independent credentials. His strongest opponent was former PAP stalwart and Member of Parliament Dr Tan Cheng Bock, most remembered for resounding victories in the now-defunct Ayer Rajah ward and speaking up fearlessly as an internal critic. He did not back down despite Dr Tony Tan's entry.

The two "Dr Tans", once Parliamentary colleagues and fellow PAP MPs for seven terms, had much in common. Both were born in the same year, entered politics around the same time - the former in 1979 and the latter in 1980, stepped down in 2006 and resigned from PAP as members just before this election to fulfill the required criteria of non-partisanship. The nail-biting finish between the two led to a nation-wide recount and set a record for the second narrowest margin after the 1959 River Valley contest.

The third, Tan Jee Say, once principal private secretary to Emeritus Senior Minister Goh Chok Tong, took many by surprise by unexpectedly becoming the only former opposition candidate awarded the COE, as his qualifications were seen to be inadequate to meet the criteria. He chose a symbol used by the late Ong Teng Cheong, Singapore's first Elected President.

The fourth and only newcomer, Tan Kin Lian, was formerly chief executive officer of NTUC Income - the union umbrella's insurance arm - and secretary of PAP's Marine Parade branch under ESM Goh. After stepping down as CEO, he quit PAP and became a maverick known for standing up for mini-bonds holders. He would occasionally align himself to the opposition's activities and causes, particularly NSP and SDP.

A total of six applications were submitted. Two others who failed to qualify for the COE were Andrew Kuan and Ooi Boon Ewe, attempting their second and third application respectively, with the latter resigning from the PLDP he founded.

This was also the first time since independence that two national elections were held in one same year, photos of candidates were included in ballot papers and a Presidential candidate deposit was forfeited. Transportation of overseas votes was mildly delayed due to hurricane disaster in the United States of America, triggering airport closures in New York.

Writ of election:
  3 August 2011, Wednesday
Nomination day:
  17 August 2011, Wednesday
Polling day:
  27 August 2011, Saturday
Overseas vote-counting:
  31 August 2011, Wednesday
President swearing-in:
  1 September 2011, Thursday

  2,274,773 [OV: 5,504]
Voter turnout:
  2,156,389 [OV: 3,375] (94.8%)
Election deposit:
  $48,000 (+$10,500)

745,693 (35.2%)
[OV: 1,296]
738,311 (34.9%)
[OV: 1,183]
Tony TAN Keng Yam
71  |  M  |  Former deputy chairman & executive director
TAN Cheng Bock
71  |  M  |  Non-executive chairman & medical practitioner
530,441 (25.0%)
[OV: 709]
104,095 (4.9%)
[OV: 164]
Forfeited $48,000 deposit
TAN Jee Say
57  |  M  |  Investment adviser
TAN Kin Lian
63  |  M  |  Consultancy company owner
Tony TAN Keng Yam wins by margin of 7,382 (0.3%)
Valid votes: 2,118,540 (98.2%)
[OV: 3,352]
Rejected votes: 37,849 (1.8%)
[OV: 23]