| U20 World Championships all-time decathlon records | |||||
| Event | Result | Decathlete | Nation | Points | Venue |
| 100 m | 10,51 WB (-0.3) | Ashley Moloney | AUS | 8190 | Tampere 2018 |
| Long jump (<=2.0 m/s) | 7.74 (+1.2) | Cedric Dubler | AUS | 8094 | Eugene 2014 |
| Long jump (>2.0 m/s) | 7.80 (+2.1) | Yuriy Yeryomich | BLR | DNF(7) | Eugene 2014 |
| Shot put (6 kg) | 16.94 | Aleksei Sysoyev | RUS | 8047 | Grosseto 2004 |
| Shot put (7.26 kg) | 14.71 | Ruben van Balen | NED | 6395* | Plovdiv 1990 |
| High jump | 2.16 | Andrei Krauchanka | BLR | 8126 | Grosseto 2004 |
| 400 m | 46,79 | Andrés Silva | URU | 7542 | Grosseto 2004 |
| 110 m hurdles (99 cm) | 13,70 (+0.5) | Zàlan Zemen | HUN | 7080 | Eugene 2026 |
| 110 m hurdles (107 cm) | 14,30 (-0.2) | Eric Kaiser | FRG | 7762* | Plovdiv 1990 |
| Discus throw (1.75 kg) | 53.80 | Aleksei Sysoyev | RUS | 8047 | Grosseto 2004 |
| Discus throw (2.0 kg) | 44.88 | Oleg Semyonov | URS | 7316* | Athens 1986 |
| Pole vault | 5.10 | Benjamin Jensen | NOR | 7676* | Lisbon 1994 |
| 5.10 | Štěpán Janáček | CZE | 7276* | Sydney 1996 | |
| Javelin throw | 71.59 | Niklas Kaul | GER | 8162 | Bydgoszcz 2016 |
| 1500 m | 4.13,62 | Remco van Veldhuizen | NED | 7313* | Seoul 1992 |
| 1st day | 4381 | Jente Hauttekeete | BEL | 8053 | Nairobi 2021 ↗ |
| 10,89 - 7.44 - 15.61 - 2.09 - 48,99 | |||||
| 2nd day | 4148 | Niklas Kaul | GER | 8162 | Bydgoszcz 2016 |
| 14,72 - 41.80 - 4.80 - 71.59 - 4.21,70 | |||||
| Running events | 3560 | Ashley Moloney | AUS | 8190 | Tampere 2018 |
| 10,51 - 46,86 - 14,13 - 4.42,65 | |||||
| Jumping events | 2680 | Tomas Järvinen | CZE | 8425 | Lima 2024 |
| 7.66 - 2.12 - 4.60 | |||||
| Throwing events (U20) | 2658 | Jake Stein | AUS | 7955 | Barcelona 2012 |
| 16.39 - 51.43 - 69.61 | |||||
| Throwing events (senior)* | 2187 | Oleg Semyonov | URS | 7316* | Athens 1986 |
| 13.47* - 44.88* - 59.26 | |||||
| Decathlon | 8425 NR CR | Tomas Järvinen | CZE | 8425 | Lima 2024 |
| 10,82 - 7.66 - 13.54 - 2.12 - 48,88 - 13,78 - 49.18 - 4.60 - 55.79 - 4.29,78 | |||||
| U20 World Championships all-time decathlon champions | ||||
| Year | Venue | Decathlete | Nation | Points |
| 1986 | Athens 1986 | Petri Keskitalo | FIN | 7623 CR * |
| 1988 | Sudbury 1988 | Michael Kohnle | FRG | 7729 CR * |
| 1990 | Plovdiv 1990 | Eric Kaiser | FRG | 7762 CR * |
| 1992 | Seoul 1992 | Raul Duany Bueno | CUB | 7403 * |
| 1994 | Lisbon 1994 | Benjamin Jensen | NOR | 7676 * |
| 1996 | Sydney 1996 | Attila Zsivoczky | HUN | 7582 * |
| 1998 | Annecy 1998 | Aki Heikkinen | FIN | 7476 * |
| 2000 | Santiago 2000 | Dennis Leyckes | GER | 7897 CR * |
| 2002 | Kingston 2002 | Leonid Andreyev | UZB | 7693 CR |
| 2004 | Grosseto 2004 | Andrei Krauchanka | BLR | 8126 NR CR |
| 2006 | Beijing 2006 | Arkadi Vasilyev | RUS | 8059 CR |
| 2008 | Bydgoszcz 2008 | Jan Felix Knobel | GER | 7896 |
| 2010 | Moncton 2010 | Kevin Mayer | FRA | 7928 |
| 2012 | Barcelona 2012 | Gunnar Nixon | USA | 8018 |
| 2014 | Eugene 2014 | Jiri Sykora | CZE | 8135 CR |
| 2016 | Bydgoszcz 2016 | Niklas Kaul | GER | 8162 CR |
| 2018 | Tampere 2018 | Ashley Moloney | AUS | 8190 NR CR |
| 2021 | Nairobi 2021 ↗ | František Doubek | CZE | 8169 |
| 2022 | Cali 2022 | Gabriel Emmanuel | NED | 7860 |
| 2024 | Lima 2024 | Tomas Järvinen | CZE | 8425 NR CR |
| 2026 | Eugene 2026 | Liam Belo Da Silva | SWE | 8112 NR |
Senior implements were used until 2000: shot put 7.26 kg, hurdles 107 cm and discus 2.0 kg. The 6 kg shot and 1.75 kg discus were introduced in 2002; the hurdles were lowered to 99 cm in 2006. Championship records refer to the specifications used in each period. National records shown here refer to the U20 category.
NR – national record
CR – championship record
WB – world best
↗ – high altitude event
DNF – did not finish
* – senior implements (shot put 7.26 kg, hurdles 107 cm, discus 2.0 kg)