- Sep 1 Timberlake Westenbaker's "Our Country's Good" premieres in London
- Sep 3 Estimated by this date 50,000 Kurdish civilians and soldiers killed by Iraq, many using chemical weapons, in aftermath of Iran-Iraq War
- Sep 6 Crippled soviet Soyuz TM-5 lands safely with 2 cosmonauts aboard
- Sep 6 Thomas Gregory (11) swims English Channel
- Sep 6 USSR performs underground nuclear test
- Sep 7 Security & Exchange Commission accuses Drexel of violating security laws
- Sep 10 -18] Hurricane Gilbert, kills 300 in Jamaica, Texas & Yucatan
- Sep 11 1/3 of population argues for Estonia autonomy
- Sep 12 Gilbert, strongest hurricane ever (160 mph), devastates Jamaica
- Sep 13 9 hard/software manufacturers announce EISA computer bus in NY
- Sep 13 Gilbert is strongest (26.13 barometer) hurricane in Western Hemisphere
- Sep 14 USSR performs nuclear test at Eastern Kazakh/Semipalitinsk USSR
- Sep 15 Museum of Moving Image in London opens
- Sep 18 Coup in Haiti: General Prosper Avril takes control, Henri Namphy flees
- Sep 18 Burma suspends its constitution
- Sep 18 Magna Charta Universitatum signed to celebrate university traditions and mark 900th anniversary of the founding of Bologna University, the oldest in the world
- Sep 19 Israel launches 1st satellite, for secret military reconnaissance
- Sep 22 Canada begins production of a $5 silver Maple Leaf bullion coin
- Sep 23 Fiji's new constitution is proposed
- Sep 23 Premiere of director Paul Schrader's crime biopic "Patty Hearst"
- Sep 24 Barbara C Harris of Mass, elected 1st woman Episcopal bishop
- Sep 24 Canada's Ben Johnson runs drug-assisted 100m in 9.79 sec
- Sep 24 Dave Stieb has no-hitter broken up with 2 outs in the 9th
Beatification
Sep 25 Pope John Paul II beatifies Friar Junípero Serra (founder of 1st Californian missions)
- Sep 26 Canada's Ben Johnson stripped of his 100-m gold failing drug test
- Sep 26 NYC's Rockefeller Center declared a national landmark
- Sep 26 Polish communist party picks propaganda chief Rakowski as new PM
- Sep 26 US space shuttle STS-26 launched
- Sep 27 Grand jury evidence shows Tawana Brawley fabricated rape story
- Sep 27 Senate votes for major federal tax code changes
Historic Event
Sep 27 The National League for Democracy, led by Aung San Suu Kyi is founded in Burma (Myanmar)
- Sep 27 Canadian Finn class sailor Lawrence Lemieux abandons race 5 to assist injured competitor after being in 2nd place; selfless act is awarded with the Pierre de Coubertin medal
- Sep 28 Bronx Museum for Arts opens
- Sep 29 26th NASA Space Shuttle Mission: Discovery 7 launches
- Sep 29 China performs nuclear test at Lop Nor, PRC
- Sep 29 UN peacekeeping forces win Nobel Peace prize
- Sep 29 Union Station reopens in Washington, D.C.
- Sep 30 Andrei Andreyevich Gromyko retires as Soviet Foreign Minister
- Sep 30 Dave Stieb loses 2nd consecutive no hitter bid with 2 outs in 9th
- Sep 30 IBM announces shipment of 3 millionth PS/2 personal computer