- U.S. and Iraqi Troops Attack Insurgents (Oct. 1): More than 5,000 soldiers attempt to take over Samarra, held by militants. As many as 125 insurgents killed. (Oct. 3): U.S. and Iraqi troops take control of Samarra.
- Bomb Explodes at Pakistani Mosque (Oct. 1): Nearly two dozen killed when bomb tears throw Shiite mosque in Sialkot.
- Three Suicide Bombers Strike in Iraq (Oct. 4): Two car bombs explode in Baghdad. The third hits in Mosul. Deaths total 26.
- Khmer Rouge Leaders to Face Trial (Oct. 4): Cambodia's lower house of parliament ratifies UN agreement to create tribunal to try leaders of murderous regime.
- Report Concludes No Illicit Weapons in Iraq (Oct. 6): Final report by chief weapons inspector Charles Duelfer says Iraq “essentially destroyed” all illicit weapons by the end of 1991 and had no such programs underway. Report also says Saddam Hussein had intended to resume weapons program.
- Cambodian King Abdicates (Oct. 7): Move by King Norodom Sihanouk casts confusion over country as there's no clear successor. (Oct. 11): Throne Council names his son Prince Norodom Sihamoni king.
- Israelis Targeted in Egypt (Oct. 8): At least 30 people die in three bombings at three resorts in the Sinai Peninsula.
- Briton Beheaded in Iraq (Oct. 8): Insurgent group One God and Jihad claims responsibility for death of engineer Kenneth Bigley.
- Afghanistan Holds Elections (Oct. 9): Turnout high for presidential election. President Hamid Karzai and 17 other candidates on ballot. Karzai's rivals allege corruption and fraud. (Oct. 10): The UN says it will form an independent commission to investigate the election. (Oct. 24): Karzai wins election, taking 55.3% of the vote, according to preliminary results.
- Rebel Army Gives Up Weapons (Oct. 11): Moktada al-Sadr's Mahdi Army begins to surrender heavy weapons. Results deemed a “mixed success.”
- Bombs Explode in Baghdad's Guarded Site (Oct. 14): Insurgents detonate two bombs in the Green Zone, home to Iraqi officials and the American Embassy.
- Israeli Troops Withdraw from Gaza (Oct. 16): Move ends deadly 17-day offensive to stop Palestinians from firing rockets into Israeli settlements; 109 Palestinians killed.
- Aid Worker Kidnapped in Iraq (Oct. 19): Margaret Hassan, British-Iraqi director of CARE International, abducted in Baghdad.
- Dozens of Iraqi Soldiers Killed (Oct. 24): Fifty new soldiers executed by insurgents loyal to Abu Musab al-Zarqawi.
- Tons of Explosives Missing in Iraq (Oct. 25): New York Times reports that about 380 tons of powerful explosives disappeared from military installation called Al Qaqaa sometime after the U.S.-led war began in 2003.
- Israeli Parliament Approves Sharon Plan (Oct. 26): Votes, 67–45, in favor of prime minister's proposal to remove settlements and soldiers from the Gaza Strip and parts of the West Bank.
- Arafat Seeks Medical Treatment (Oct. 29): Palestinian leader Yasir Arafat, who has been ill with a stomach ailment, travels to a Paris hospital.
- Rumsfeld Plays Down Iraq–al-Qaeda Link (Oct. 4): Tells Council on Foreign Relations that he sees no “strong, hard evidence” of a connection.
- Former Iraq Administrator Critical of Troop Deployment (Oct. 4): Paul Bremer says that President Bush failed to send enough soldiers to secure Iraq.
- Candidates Debate Issues (Oct. 5): Vice President Dick Cheney and Sen. John Edwards aggressively attack each other's records in their first and only debate. War in Iraq dominates session. (Oct. 8): President Bush and Sen. John Kerry field questions from undecided voters in a town-hall-style debate. (Oct. 14): In final debate, candidates attack each other's domestic policies.
- Ethics Committee Criticizes DeLay (Oct. 6): House majority leader Tom DeLay faulted for questionable fund-raising tactics and for asking federal officials to intervene in state issue regarding gerrymandering.
- Chief Justice Has Cancer (Oct. 25): Supreme Court announces that William Rehnquist is undergoing treatment for thyroid cancer.
- Mt. St. Helens Erupts (Oct. 1): After almost two decades of dormancy, the Washington volcano erupts in a small explosion of steam and ash. No deaths, damage, or injuries reported.
- SpaceShipOne Wins X Prize (Oct. 4): The privately funded manned spacecraft flies above the Earth's atmosphere for the second time in a week, winning the $10 million Ansari X Prize.
- Flu Vaccine Contaminated (Oct. 5): Half of the country's flu vaccine to be destroyed because its maker, Chiron Corp., had its manufacturing license suspended.
- Economy Adds Jobs (Oct. 9): Labor Department reports employment increased by less than 100,000 jobs. Jobless rate remains at 5.4%.
- Malaria Vaccine Proves Promising (Oct. 15): Director of the Malaria Vaccine Initiative says vaccine tested on children in Mozambique prevented disease in 30% of cases and prevented life-threatening illness 58% of the time.
- Skeletons of Tiny People Found (Oct. 28): Australian and Indonesian archaeologists have unearthed skeletons of tiny people who are being called Homo floresiensis. These 3-foot-tall people had very long arms, heads the size of grapefruit, and are believed to have disappeared only 13,000 years ago, or perhaps even more recently.