The track, which was at the summit of the UK singles chart for four weeks earlier this year, vaults from 19 to one following her performance at last week's MTV VMAs.
The song sold over 270,000 downloads in its ninth week on the tally to give the singer her second US number one single, following 'Rolling in the Deep' in May this year.
Meanwhile, Maroon 5 and Christina Aguilera's 'Moves Like Jagger' dips to two, and Foster the People's 'Pumped Up Kicks' remains at three.
Lady GaGa's 'You and I' leaps from 16 to six, and Cobra Starship's 'You Make Me Feel' jumps from 18 to number eight.
Further down the chart, eight songs from Lil Wayne's Tha Carter IV album debut on the tally after topping the albums chart earlier this week. The highest entry is the Bruno Mars-assisted 'Mirror', which lands at 16.
Elsewhere, Beyoncé's 'Love On Top' starts at 20, and Young the Giant's 'My Body' debuts at 65.
The Top 10 singles in full (click where possible for our reviews):
1. (19) Adele: 'Someone Like You'
2. (1) Maroon 5 ft. Christina Aguilera: 'Moves Like Jagger'
3. (3) Foster the People: 'Pumped Up Kicks'
4. (2) LMFAO: 'Party Rock Anthem'
5. (6) Nicki Minaj: 'Super Bass'
6. (16) Lady GaGa: 'You and I'
7. (4) Bad Meets Evil ft. Bruno Mars: 'Lighters'
8. (18) Cobra Starship ft. Sabi: 'You Make Me Feel'
9. (9) Pitbull ft. Ne-Yo, Afrojack & Nayer: 'Give Me Everything'
10. (5) Katy Perry: 'Last Friday Night (T.G.I.F)'
Watch the 'Someone Like You' music video below: