| | Miles | Kilometers | |
| 1 | Nile (Africa) | | |
| 2 | Amazon (S. America) | | |
| 3 | Chang Jiang (Yangtze) (China) | | |
| 4 | Huang He (Yellow River) (China) | | |
| 5 | Ob-Irtysh (Russia) | | |
| 6 | Amur (Asia) | | |
| 7 | Lena (Russia) | | |
| 8 | Congo (Africa) | | |
| 9 | MacKenzie (Canada) | | |
| 10 | Mekong (Viet Nam) | | |
| 11 | Niger (Africa) | | |
| 12 | Yenisey (Russia) | | |
| 13 | Parana (S. America) | | |
| 14 | Mississippi (U.S.) | | |
| 15 | Missouri (U.S.) | | |
| 16 | Murray-Darling (Australia) | | |
| 17 | Volga (Russia) | | |
| 18 | Purus (Brazil) | | |
| 19 | Madeira (Brazil) | | |
| 20 | Sao Francisco (Brazil) | | |