Swindon currently sit in 22nd position in the league, but are only two points adrift of safety. However, manager John Sheridan will be looking to resolve performances that have seen them lose three in a row going into this match.
Meanwhile, Gillingham are 16 points better off than the Robins in 13th place, with a comfortable mid-table finish looking likely for them this season.
Midfielder Hallam Hope will require a late fitness test after suffering from back spasms, but otherwise Swindon will go into the match with no fresh injury concerns.
Swindon Town (4-4-2): Trueman - Caddis, Conroy, Broadbent, Thompson - Palmer, Twine, Lyden, Payne - Garrick, Pitman.
Gillingham (4-2-3-1): Bonham - McKenzie, Cundy, Tucker, Ogilvie - Dempsey, O'Keefe - Graham, Lee, O'Connor - Oliver.
At the moment only bottom of the division Rochdale are on a worse losing streak than Swindon. Three successive defeats to Sunderland, Accrington Stanley and Oxford United have seen the club fall back into the relegation zone after a good set of results in February had resulted in them breaking out. Sheridan will need to quickly turn things around if they are to fight for survival once more.
It has been the story of Gillingham's season, but the Kent side have remained consistently inconsistent. Two excellent home results to defeat Milton Keynes Dons 3-2 and Ipswich Town 3-1 had seen them briefly break into the top half. However, a 1-0 loss to Fleetwood Town on Tuesday night once again set them back.
Ones to watch
Scott Twine may be the one to watch for Swindon. The midfielder has been a creative influence in the side since being recalled from his loan at Newport County. His ability to strike from distance is apparent, as seen with a goal of the season contender against Ipswich in January, which makes him a danger from anywhere in the opposition half.
The 21-year-old has received much praise from fans in the process, and his contributions may be the difference in Swindon staying up or not.
Vadaine Oliver will be the one to watch for Gillingham. The striker has been in fine form, netting four goals in his last four matches, overtaking Jordan Graham to be top scorer in the squad in the process.
His ability in the air is also immense, with Oliver having won more aerial duels than anyone else in League One. He'll be a threat that the Swindon defence will need to be wary of.
The last time these sides met was in the reverse fixture this season back in December. Gillingham triumphed 2-0 on that occasion, with efforts from Vadaine Oliver and Trae Coyle sealing the three points at the Priestfield Stadium.
Before that encounter it had been a few years since the teams had faced one another, with Swindon defeating the Gills 3-1 in League One in February 2017. The Robins also lead the way in terms of overall victories, with 36 wins compared to Gillingham's 33. There have also been 30 occasions when the points have been shared.
How to watch
The game has not been selected for TV coverage in the UK, but an iFollow pass can be purchased for £10 via either club's website to stream the game live.
Kick-off is scheduled for 13:00 GMT.