US Masters Golf
Apr 6 16th US Masters Tournament, Augusta National GC: Sam Snead wins his second green jacket by 4 strokes over Jack Burke Jr

Sam Snead
- Apr 8 US President Harry Truman seizes steel mills to avert a strike
- Apr 9 Hugo Ballivian's government is overthrown by the Bolivian National Revolution, starting a period of agrarian reform, universal suffrage and the nationalisation of tin mines
- Apr 11 The Battle of Nanri island takes place.
- Apr 12 Salaheddine Baccouche forms Tunisian government
- Apr 15 Franklin National Bank issues 1st bank credit card
- Apr 15 Stanley Cup Final, Olympia Stadium, Detroit, MI: Detroit Red Wings beat Montreal Canadiens, 3-0 for a 4-0 series sweep
- Apr 15 US performs nuclear test at Nevada Test Site
- Apr 15 The maiden flight of the B-52 Stratofortress prototype
- Apr 16 "4 Saints in 3 Acts" opens at Broadway Theater NYC for 15 performances
- Apr 21 56th Boston Marathon won by Doroteo Flores of Guatemala in 2:31:53
- Apr 21 BOAC begins 1st passenger service with jets (London-Rome route)
- Apr 21 Secretaries' Day (now Administrative Professionals' Day) is first celebrated
- Apr 22 1st atomic explosion on network news, Nob, Nevada
- Apr 22 Eugene Ionesco's "Les Chaises" premieres in NYC
- Apr 23 Bob Cain of Browns & Bob Feller of Indians each pitch a one-hitter
- Apr 23 New York Giant Hoyt Wilhelm wins his 1st relief game & hits his only HR
- Apr 23 Oil pipeline from Kirkuk to Banias completed
- Apr 25 6th NBA Championship: Minneapolis Lakers beat NY Knicks, 4 games to 3
- Apr 25 American Bowling Congress approves use of an automatic pinsetter
- Apr 25 German state of Bathe-Wurttemberg forms
- Apr 26 Patty Berg scores 64, best competitive round of golf by a woman
- Apr 26 US minesweeper Hobson rams aircraft carrier Wasp, kills 176
- Apr 27 "4 Saints in 3 Acts" closes at Broadway Theater NYC after 15 performances
- Apr 28 St Louis Browns lend 2 black minor leaguers to Hankyu Braves of Japan
- Apr 28 WW II Pacific peace treaty takes effect
Event of Interest
Apr 28 Dwight D. Eisenhower resigns as Supreme Commander of NATO

Dwight D. Eisenhower
- Apr 30 Mr Potato Head is 1st toy advertised on television