Mario Kart Wii sold 8.94 million units in the three biggest software markets globally, according to new information in a report released by The NPD Group, GfK Chart-Track and Enterbrain.
The title sold 5 million units in the US, 2 million in Japan and 1.94 million in the UK to take top spot.
Wii Fit was in second place, on 8.31 million, shifting 4.55 million, 2.15 million and 1.61 million in the territories respectively.
Slightly surprising on the surface was that record-breaking Grand Theft Auto IV only came third on the list, with 7.29 million units - but that was thanks to very quiet sales in Japan in comparison to Nintendo's hits. It sold 5.18 million copies in the US, 1.85 million in the UK, but only 256,000 in Japan.
Super Smash Bros Brawl was fourth, with 6.32 million units sod mostly in the US and Japan, while Call of Duty: World at War was fifth on the list based on sales in the US and UK only.
The list is as follows, broken down as: Total (US/Japan/UK)
1. Mario Kart Wii: 8.94 million (5m/2m/1.94m)
2. Wii Fit: 8.31 million (4.55m/2.15m/1.61m)
3. Grand Theft Auto IV: 7.29 million (5.18m/256k/1.85m)
4. Super Smash Bros Brawl: 6.32 million (4.17m/1.75m/404k)
5. Call of Duty: World at War: 5.89 million (4.46m/0/1.43m)