- Mar 5 The Jharkhand Party is founded in India.
- Mar 8 WAGA TV channel 5 in Atlanta, GA (CBS) begins broadcasting
- Mar 8 WBAP-FM, Fort Worth Texas, begins broadcasting
- Mar 9 Brigadier General Edwin K Wright, USA, ends term as deputy director of CIA
- Mar 9 England beat South Africa by scoring 174 runs in 94 minutes
- Mar 10 Detroit Tiger pitcher Art Houtteman is critically injured in an auto accident but recovers to win 15 games in 1949
- Mar 12 Ireland retains Five Nations Rugby Championship & Triple Crown with a 5-0 win over Wales at St. Helen's Ground, Swansea
- Mar 13 US Ladies' Figure Skating championship won by Yvonne C Sherman
- Mar 13 US Men's Figure Skating championship won by Richard Button
- Mar 15 WICU TV channel 12 in Erie, PA (NBC) begins broadcasting
- Mar 15 WLWD (now WDTN) TV channel 2 in Dayton, OH (NBC) begins broadcasting
- Mar 15 Cricket's master batsman Don Bradman receives his knighthood from the Governor-General of Australia, the Rt Hon. WJ McKell at the investiture in Queen’s Hall, Parliament House, Melbourne
- Mar 16 KFMB TV channel 8 in San Diego, CA (CBS) begins broadcasting
Golden Globes
Mar 16 6th Golden Globes: Johnny Belinda, Laurence Olivier, & Jane Wyman win
- Mar 18 WGAL TV channel 8 in Lancaster, PA (NBC) begins broadcasting
- Mar 19 1st museum devoted exclusively to atomic energy, Oak Ridge, Tennessee
- Mar 20 LPGA Titleholders Championship Women's Golf, Augusta CC: Amateur Peggy Kirk wins her only major title by 2 strokes from Patty Berg and Dorothy Kirby
- Mar 21 WTVJ TV channel 4 in Miami, FL (NBC/CBS) begins broadcasting
- Mar 23 Sidney Kingsley's "Detective Story" premieres in NYC
Academy Awards
Mar 24 21st Academy Awards: "Hamlet", Laurence Olivier & Jane Wyman win, Walter & John Huston become 1st father-and-son team to win awards
- Mar 24 SS police chief in the Netherlands Hanns Albin Rauter's request for a pardon denied, executed by firing squad
- Mar 25 The Soviet Union begins Operation Pribioi, the mass deportation of 90,000 Estonians, Latvians and Lithuanians to inhospitable areas in the Soviet Union
- Mar 26 11th NCAA Men's Basketball Championship: Kentucky beats Oklahoma State, 46-36; Wildcats' back-to-back titles; center Alex Groza MOP
- Mar 26 103rd Grand National: Leo McMorrow aboard 66/1 outsider Russian Hero wins by a comfortable 8 lengths ahead of Roimond
- Mar 29 Turkey recognizes Israel
- Mar 30 Riot breaks out in Austurvöllur square in Reykjavík, when Iceland joins NATO
- Mar 31 Newfoundland becomes Canada's 10th province