2018 FINA World Swimming Championships (25 m) – Men's 100 metre backstroke
The men's 100 metre backstroke competition of the 2018 FINA World Swimming Championships was held on 11 and 12 December 2018.
Records
Prior to the competition, the existing world and championship records were as follows.| Name | Nation | Time | Location | Date | |
| World record | Xu Jiayu | 48.88 | Tokyo | 11 November 2018 | |
| Championship record | Stanislav Donets | 48.95 | Dubai | 19 December 2010 |
Results
Heats
The heats were started on 11 December at 10:52.| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| 1 | 3 | 4 | Guilherme Guido | 49.57 | Q, SA | |
| 2 | 4 | 8 | Ryan Murphy | 49.72 | Q | |
| 3 | 4 | 4 | Xu Jiayu | 49.83 | Q | |
| 4 | 3 | 0 | Matt Grevers | 50.12 | Q | |
| 5 | 4 | 3 | Robert Glință | 50.22 | Q | |
| 6 | 4 | 5 | Mitch Larkin | 50.27 | Q | |
| 7 | 3 | 3 | Christian Diener | 50.28 | Q | |
| 8 | 5 | 5 | Simone Sabbioni | 50.62 | Q | |
| 9 | 3 | 5 | Radosław Kawęcki | 50.73 | Q | |
| 9 | 5 | 6 | Ryosuke Irie | 50.73 | Q | |
| 11 | 5 | 4 | Kliment Kolesnikov | 50.76 | Q | |
| 12 | 4 | 6 | Apostolos Christou | 50.92 | Q | |
| 13 | 3 | 6 | Guilherme Basseto | 50.94 | Q | |
| 14 | 3 | 1 | Anton Lončar | 51.09 | Q | |
| 15 | 5 | 3 | Andrei Shabasov | 51.16 | Q | |
| 16 | 2 | 4 | Thomas Ceccon | 51.30 | Q | |
| 17 | 4 | 1 | Gabriel Lopes | 51.48 | NR | |
| 18 | 4 | 7 | Viktar Staselovich | 51.59 | ||
| 19 | 5 | 2 | Markus Lie | 51.60 | ||
| 20 | 3 | 8 | Bradlee Ashby | 51.61 | ||
| 21 | 5 | 7 | Tomáš Franta | 51.82 | ||
| 22 | 2 | 3 | Omar Pinzón | 51.87 | ||
| 23 | 4 | 2 | Yuma Edo | 51.88 | ||
| 24 | 3 | 9 | Conor Ferguson | 52.04 | ||
| 25 | 3 | 7 | Hugo González | 52.05 | ||
| 26 | 3 | 2 | Cătălin Ungur | 52.28 | ||
| 27 | 5 | 8 | Bernhard Reitshammer | 52.34 | ||
| 28 | 5 | 1 | Li Guangyuan | 52.36 | ||
| 29 | 2 | 2 | Paul Lê Nguyễn | 52.48 | ||
| 30 | 5 | 0 | Dávid Földházi | 52.60 | ||
| 31 | 5 | 9 | İskender Başlakov | 52.79 | ||
| 32 | 4 | 0 | Thierry Bollin | 53.02 | ||
| 33 | 4 | 9 | Chuang Mu-lun | 53.81 | ||
| 34 | 1 | 8 | Merdan Atayev | 54.29 | ||
| 35 | 2 | 7 | Ģirts Feldbergs | 54.79 | ||
| 36 | 1 | 1 | Cadell Lyons | 54.92 | ||
| 37 | 2 | 5 | Lee Ju-ho | 55.02 | ||
| 38 | 2 | 6 | Armando Barrera Aira | 55.07 | ||
| 39 | 2 | 9 | Filippos Iakovidis | 55.87 | NR | |
| 40 | 2 | 0 | Matthew Mays | 56.09 | ||
| 41 | 1 | 4 | Eisner Barberena Espinoza | 56.78 | ||
| 42 | 1 | 7 | Heriniavo Michael Rasolonjatovo | 59.02 | ||
| 43 | 1 | 5 | Abdulaziz Al-Obaidly | 59.41 | ||
| 44 | 1 | 3 | Bede Aitu | 59.68 | ||
| 45 | 1 | 2 | Omar Al-Rowaila | |||
| 46 | 1 | 6 | Joel Gjini | |||
| 47 | 1 | 0 | Ali Imaan | |||
| 2 | 8 | Driss Lahrichi |
Semifinals
The semifinals were started on 11 December at 19:17.| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| 1 | 2 | 5 | Xu Jiayu | 49.21 | Q | |
| 2 | 2 | 4 | Guilherme Guido | 49.45 | Q, SA | |
| 3 | 1 | 4 | Ryan Murphy | 49.52 | Q | |
| 4 | 2 | 7 | Kliment Kolesnikov | 49.62 | Q | |
| 5 | 1 | 5 | Matt Grevers | 49.97 | Q | |
| 6 | 2 | 3 | Robert Glință | 49.98 | Q, NR | |
| 7 | 2 | 6 | Christian Diener | 50.04 | Q | |
| 8 | 1 | 3 | Mitch Larkin | 50.12 | Q | |
| 9 | 1 | 6 | Simone Sabbioni | 50.21 | ||
| 10 | 2 | 8 | Andrei Shabasov | 50.32 | ||
| 11 | 2 | 2 | Radosław Kawęcki | 50.43 | ||
| 12 | 1 | 2 | Ryosuke Irie | 50.45 | ||
| 13 | 2 | 1 | Guilherme Basseto | 50.83 | ||
| 14 | 1 | 7 | Apostolos Christou | 50.91 | ||
| 15 | 1 | 8 | Thomas Ceccon | 50.96 | ||
| 16 | 1 | 1 | Anton Lončar | 51.20 |
Final
The final was held on 12 December at 19:08.| Rank | Lane | Name | Nationality | Time | Notes |
| 3 | Ryan Murphy | 49.23 | |||
| 4 | Xu Jiayu | 49.26 | |||
| 6 | Kliment Kolesnikov | 49.40 | |||
| 4 | 8 | Mitch Larkin | 49.46 | ||
| 5 | 5 | Guilherme Guido | 49.75 | ||
| 6 | 2 | Matt Grevers | 50.02 | ||
| 7 | 1 | Christian Diener | 50.24 | ||
| 8 | 7 | Robert Glință | 50.36 |