[4] Prime Minister Tarō Asō conceded late on the night of August 30, 2009, that the LDP had lost control of the government, and announced his resignation as party president.

The 2009 election was the first time since World War II that voters mandated a change in control of the government to an opposition political party.

Due to the characteristics of the Japanese election system, the LDP ended up with 296 seats in the Lower House (61.6%), which enabled Koizumi to complete the privatization of Japan Post.

Since then Japan had three further prime ministers (Shinzō Abe, Yasuo Fukuda and Tarō Asō) who came to power without there being a general election.

[8] Media sources speculated that, in the wake of a recent change in leadership, Prime Minister Taro Aso might call elections in late October or early November 2008 while his popularity was still high.

[9] There were expectations that the steady decline and numerous scandals of the LDP might lead to the complete extinction of the party and the creation of a new political system, with actual ideologically coherent parties emerging instead of the current system of a shared interest in power with stark ideological differences.

[12] As soon as the election was called, a campaign was underway by a group of LDP Diet Members to replace Aso as leader.

[16] The DPJ's policy platforms include: a restructuring of civil service; a monthly allowance for families with children (at 26000 yen per child); a cut in the fuel tax; income support for farmers; free tuition for public high schools; the banning of temporary work in manufacturing;[17] raising the minimum wage to 1000 yen; and the halting of any increase in sales tax for the next four years.

Many based their predictions on the low approval rating of the Prime Minister Taro Aso and the devastating loss that the LDP suffered in the earlier prefectural election in Tokyo.

[30] The DPJ won a strong majority in the House of Representatives, thus virtually assuring that Hatoyama would be the next prime minister.

[32] For the same reason, one Democratic Kinki proportional seat that had fallen vacant in 2010 (previously held by Mitsue Kawakami) could not be filled until the next general election.

In March 2011, the Supreme Court decided that the malapportionment of electoral districts in the 2009 election had been in breach of the Constitution of Japan.