- Oct 2 The economic crisis in Ireland is considered to be the driving force behind the largest migration of Irish people to London in 20 years, it is reported today
- Oct 2 The International Olympic Committee votes to award Rio de Janeiro, Brazil rights to host the 2016 Summer Olympics and Paralympics
Farm Aid 22
Oct 4 Farm Aid 22 held in Maryland Heights, Missouri; performers include Willie Nelson, John Mellencamp, Neil Young, Dave Matthews, Jason Mraz, and Wilco [1]
- Oct 4 George Papandreou's Panhellenic Socialist Movement defeats Greece's governing New Democracy party in an electoral landslide.
Senior Players Championship
Oct 4 Senior Players Championship Men's Golf, Baltimore CC: Jay Haas wins his third and final Champions Tour major title by 1 stroke from Tom Watson
- Oct 5 Australia wins cricket's Champions Trophy at Centurion Park in Gauteng, South Africa by 6 wickets (28 balls remaining) v New Zealand; chasing 200, Shane Watson is 105 not out in Australia's 206/4
- Oct 5 ICC Men's Cricket Champions Trophy, Centurion Park, Gauteng: Australia beats New Zealand by 6 wickets for their second title; Player of the series: Ricky Ponting, AUS 288 runs
The List
Oct 6 Manhattan Records releases "The List", the twelfth studio album by singer Rosanne Cash, with song selections culled from a list of 100 titles that her father compiled and gave her when she decided to pursue a career in music.; the album features guest appearances by Bruce Springsteen, Jeff Tweedy, Elvis Costello, and Rufus Wainwright
Carl Gustav Jung's Red Book
Oct 7 A digital version of psychiatrist Carl Gustav Jung's 'Red Book' is published 48 years after his death and contains personal notes on his subconscious during the period in which he developed his principal theories
- Oct 9 First lunar impact of the Centaur and LCROSS spacecrafts as part of NASA's Lunar Precursor Robotic Program
- Oct 10 After closed borders for nearly two hundred years, Armenia and Turkey sign protocols in Zurich to open their borders
- Oct 11 Presidents Cup Golf, Harding Park GC: US down International team, 19½–14½; their 2nd consecutive win by that score and 3rd straight overall
Birgit Nilsson Prize
Oct 14 Spanish opera singer Plácido Domingo is awarded the first $1 million Birgit Nilsson Prize
- Oct 18 British Mercedes driver Jenson Button finishes 5th in Brazilian Grand Prix at Autódromo José Carlos Pace to clinch his first F1 World Drivers Championship
- Oct 21 55th National Film Awards (India): "Kanchivaram" wins the Golden Lotus
- Oct 21 MLB National League Championship: Philadelphia Phillies beat Los Angeles Dodgers, 4 games to 1
Gregorio Álvarez Sentenced
Oct 22 Former Uruguayan dictator Gregorio Álvarez sentenced to 25 years in prison for aggravated murder of 37 Uruguayan dissidents who had fled to Argentina [1]
- Oct 22 Microsoft releases Windows 7
- Oct 23 The UK markets had contracted by 0.4% in the third quarter against what was expected to be a period of growth, as a result of unexpectedly poor performance by the service sector
- Oct 23 The United Nations "Rotterdam Rules" convention regulating international maritime carriage of goods is ratified with its twentieth signature.
- Oct 24 19th College Football Holy War: Notre Dame beats Boston College 20-16 in South Bend (Notre Dame's first win in the series in nine years)
- Oct 24 First International Day of Climate Action, organized with 350.org, a global campaign to address a claimed global warming crisis.
- Oct 25 MLB American League Championship: New York Yankees beat Los Angeles Angels of Anaheim, 4 games to 2
- Oct 25 The 25 October 2009 Baghdad bombings kills 155 and wounds at least 721.
- Oct 28 NASA successfully launches the Ares I-X mission, the only rocket launch for its later-cancelled Constellation program.
- Oct 28 The 28 October 2009 Peshawar bombing kills 117 and wounds 213.
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