- Oct 1 US Office of Strategic Services (OSS), precursor to the CIA, disbands
- Oct 3 Detroit Tigers and Chicago Cubs meet in Baseball World Series for the 4th time; Hank Borowy pitches a 6-hit shutout as Cubs win Game 1, 9-0 at Briggs Stadium; Detroit wins series, 4-3
Elvis Comes Fifth in Talent Show
Oct 3 Elvis Presley's 1st public performance, at age of 10, singing "Old Shep" in youth talent contest at the Mississippi-Alabama Fair and Dairy Show, in Tupelo, Mississippi; contest is broadcast over WELO Radio, he wins fifth prize - $5.00 in fair ride tickets
- Oct 3 World Federation of Trade Unions forms; CIO a member
- Oct 5 "Meet the Press" premieres on radio
- Oct 5 Hollywood Black Friday: A six month strike by Hollywood set decorators turns into a bloody riot at the gates of Warner Brothers' studios.
- Oct 5 Indonesian army forms
Wilhelmina Visits Rotterdam
Oct 5 Queen Wilhelmina visits Rotterdam
Polonaise
Oct 6 Frédéric Chopin (as adapted by Bronislaw Kaper) and John LaTouche's musical "Polonaise", based on the life of Polish-American patriot Tadeusz Kościuszko, opens at the Alvin Theatre, later transferring to the Adelphi, NYC; runs for 113 performances
- Oct 6 Memorial for executed unveiled in Terbregge
- Oct 6 Tavern owner "Billy Goat" Sianis buys seat for his goat for Game 4 of Baseball World Series, is escorted out and casts goat curse on Chicago Cubs
Eisenhower Visits The Hague
Oct 6 US General Eisenhower welcomed in The Hague (on Hitler's train)
Nuclear Secret
Oct 8 US President Harry Truman announces atomic bomb secret shared with Britain and Canada
Chinese Civil War Begins
Oct 11 Chinese civil war begins between Kuomintang government led by Chiang Kai-Shek and Mao Zedong's Communist Party
- Oct 11 First man-made object to escape the atmosphere (WAC Corporal) is fired from White Sands Missile Range, New Mexico, reaching 235,000 feet
- Oct 14 Chicago Cardinals end a record 29-game losing streak, beat Bears
- Oct 15 Baseball Attendance hits record 10.28 million (Tigers 1.28 is highest)
- Oct 16 UN's Food & Agriculture Organization comes into existence
Loyalty Day
Oct 17 Loyalty Day in Argentina, mass demonstrations held to release Juan Perón
Robeson Wins Spingarn Medal
Oct 18 Paul Robeson wins Spingarn Medal for singing and acting achievements
- Oct 21 Women in France allowed to vote for 1st time
Robinson Signs with Royals
Oct 23 American baseball player Jackie Robinson signs contract with Montreal Royals, minor league farm team of Brooklyn Dodgers
United Nations Charter
Oct 24 Charter of United Nations comes into effect
- Oct 24 In France PC/PS/MRP win parliamentary election (25/24/23%)
Retrocession Day
Oct 25 Japanese surrender Taiwan to General Chiang Kai-shek
Getulio Vargas Resigns
Oct 29 Getulio Vargas, President of Brazil, resigns
- Oct 29 Happy Chandler resigns as US Senator, remains as baseball commissioner
- Oct 30 Branch Rickey signs Jackie Robinson to a contract with the Montreal Royals, the top minor league affiliate of the Brooklyn Dodgers
- Oct 30 US government announces end of shoe rationing
Admirals
Aviators
Gangsters
Generals
Industrialists
Suffragists