2009 World Youth Championships in Athletics – Boys' 100 metres

The Boys' 100 metres at the 2009 World Youth Championships in Athletics was held at the Brixen-Bressanone Sport Arena on 8 and 9 July. The event was won by Prezel Hardy of the United States.

Prior to the competition, the following records were as follows.

No new records were set during the competition.

Qualification rule: first 2 of each heat (Q) plus the 4 fastest times (q) qualified.

Qualification rule: first 4 of each heat (Q) qualified.

Key: PB = Personal best, SB = Seasonal best

Wind: 1.1 m/s

Key: PB = Personal best, SB = Seasonal best

Wind: 1.3 m/s

Key: PB = Personal best, SB = Seasonal best

Wind: −1.2 m/s