List of Billboard Hot 100 number-one singles of the 2000s

The Billboard Hot 100 is a chart that ranks the best-performing songs in the United States, published by Billboard magazine. In the 2000s, each chart's "week ending" date was the Saturday of the following two weeks. The data were compiled by Nielsen SoundScan based collectively on each single's weekly physical (CD, vinyl and cassette) and digital sales, airplay, and streaming. Only songs released as physical singles were counted prior to 1998, when Billboard magazine allowed airplay-only singles to chart.^[1] While Nielsen had begun tracking digital sales since 2003 for the component chart Digital Songs, it was not until the chart dated February 12, 2005, that digital performance was officially recognized as a performance indicator on the Hot 100, in the wake of decreasing traditional physical sales.^[2] On August 4, 2007, Billboard added online streaming to its methodology.^[3]

Throughout the decade, a total of 129 singles claimed the top spot of the Hot 100. While Santana's "Smooth" featuring Rob Thomas topped the chart in the first two weeks of 2000, it was not counted as a number-one single of the 2000s decade by Billboard because it had topped the chart in October 1999, and thus was counted as a number-one single of the 1990s decade only.^[4] Overall, the decade saw the dominance of hip hop and R&B releases with dance beats and pop crossover, replacing the 1990s' trend of sentimental ballads.^[5] While the first half of the 2000s saw the continued relevance of physical sales, the second half welcomed the dominance of digital sales performance thanks to advancements of the internet, through which music was widely distributed.^[6]