Music
© Wenn
The album - which was released 18 months ago - has now sold 250,000 units, and is the only UK album to sell over 200,000 copies digitally, the Official Charts Company reports.
Other high sellers in the list include Florence and the Machine's Lungs and Lily Allen's It's Not Me, It's You.
Kings Of Leon's closest challenger in the digital arena is Lady Gaga, whose debut album The Fame is likely to pass 200,000 downloads within the next month.
Official Charts Company managing director Martin Talbot said: "This is an incredible achievement by Kings Of Leon, one of the few acts in recent years to have crossed over from true alternative territory into the mainstream.
"To date, just 12 albums have passed the 100,000 download mark, but the explosive success of Kings Of Leon illustrates the growing popularity of album downloading among music fans, which has been steadily increasing over the past three years."
The biggest selling digital albums in the UK are as follows:
1. Kings of Leon: Only By The Night
2. Lady GaGa: The Fame
3. Florence and the Machine: Lungs
4. Lily Allen: It's Not Me, It's You
5. Coldplay: Viva La Vida Or Death And All His Friends
6. Duffy: Rockferry
7. Amy Winehouse: Back To Black
8. Black Eyed Peas: The E.N.D
9. The Script: The Script
10. Beyoncé: I Am Sasha Firece
More: Music
More Music News
Singles Reviews
Nelly Furtado: 'Big Hoops' reviewThe singer's comeback confidently ignores all the latest fads.
Music Interviews
David Guetta: My music isn't all the sameDigital Spy talks to the DJ ahead of his London shows this weekend.
The Sound
Playlist: Queen's Diamond Jubilee specialWe select our favourite Queen-related songs ahead of the Diamond Jubilee.
Album Reviews
Ladyhawke: 'Anxiety' reviewThe singer's ear for infectious pop remains stronger than ever on her second LP.
