The singer tops the tally for a second week, holding off Nicki Minaj's 'Starships' at two, while fun.'s 'We Are Young' holds at three.
Meanwhile, Ed Sheeran's 'Lego House' leaps 14 to five, One Direction vault 18 to six with 'One Thing' and Timomatic shift 16 to eight with 'If Looks Could Kill'.
Further down the chart, B.o.B lands at 21 with 'So Good' and Stan Walker bounds 35 to 25 with 'Music Won't Break Your Heart.
Bob Sinclar, Pitbull and Fatman Scoop's start at 39 with 'Rock The Boat', Pitbull's 'Back In Time' is at 42, and Rebecca Ferguson debuts at 43 with 'Nothing's Real But Love'.
The Top 10 singles in full (click where possible for our reviews):
1. (1) Carly Rae Jepsen: 'Call Me Maybe'
2. (2) Nicki Minaj: 'Starships'
3. (3) fun. ft. Janelle Monae: 'We Are Young'
4. (4) Labrinth ft. Tinie Tempah: 'Earthquake'
5. (14) Ed Sheeran: 'Lego House'
6. (18) One Direction: 'One Thing'
7. (6) Skrillex: 'Bangarang'
8. (8) Timomatic: 'If Looks Could Kill'
9. (7) Gym Class Heroes ft. Neon Hitch: 'Ass Back Home'
10. (9) Jason Derulo: 'Fight For You'
Watch Carly Rae Jepsen's 'Call Me Maybe' music video below: