List of Billboard Hot 100 number ones of 1999

The Billboard Hot 100 is a chart that ranks the best singles of the United States.

Published by Billboard magazine, the data are compiled by Nielsen SoundScan based collectively on each single's weekly physical sales and airplays.

The first of these, "I'm Your Angel" by R. Kelly and Celine Dion, spent two weeks at the top, concluding a six-week run that had begun in December 1998.

During the year, 11 acts had achieved a first U.S. number-one single, including: Britney Spears, Ricky Martin, Jennifer Lopez, Destiny's Child, Dru Hill, Kool Moe Dee, Christina Aguilera, Enrique Iglesias, Jay-Z, Santana, and Rob Thomas.

The longest running number-one single is "Smooth" by Santana featuring Matchbox Twenty frontman Rob Thomas, which attained 12 weeks at number-one.

Santana and Rob Thomas ' " Smooth " was the longest-running single of 1999, topping the chart for 10 consecutive weeks.
Pop singer Cher earned her first number-one single since 1974 and fifth overall when " Believe " topped the chart.
Pop singer Christina Aguilera earned her first U.S. number-one single, " Genie in a Bottle ".
Spanish singer Enrique Iglesias earned his first U.S. number-one single with " Bailamos " which stayed for two consecutive weeks.
Pop singer Britney Spears earned her first U.S. number-one peak with " ...Baby One More Time ".
Singer Ricky Martin earned his first U.S. number-one single with " Livin' la Vida Loca ".