List of Billboard Adult Top 40 number-one songs of the 1990s
The Adult Top 40 chart is published weekly by "Billboard" magazine and ranks "the most popular adult top 40 as based on radio airplay detections measured by Nielsen BDS." The chart was first published in the March 16, 1996, issue of "Billboard"; however, historically, the chart's introduction was in October 1995, when it began as a test chart. The Adult Top 40 chart was formed following a split of the "Hot Adult Contemporary" chart due to the growing emergence of Adult Top 40 radio stations in the  1990s. These stations played a wider variety of artists and saw a faster turnover of songs compared to traditional adult contemporary radio. Songs by modern rock, dance, and R&B artists were mixed in with acts more closely associated with adult contemporary. According to "Billboard", splitting the chart "better reflect[s] the music being played on adult contemporary and adult/top 40 stations."