The Mars Zeon first appears in the manga series Mobile Suit Gundam F90, being a group of Principality of Zeon army remnants who fled to Mars, rather than to Axis, after the One Year War. The Mars Zeons were also nicknamed the Oldsmobile Army by the Federation, because of their use of mobile suits of old-style appearances.
Enduring on their own for a long time, the Mars Zeon was later reinforced by remnants of the second Neo Zeon movement. Using the former Neo Zeon members' AMS-119 Geara Doga mobile suits, The Mars Zeon were able to produce mobile suits, outwardly similar to the Principality's most famous designs, but possessing performance superior to the Geara Doga. Mars Zeon first made their presence known in U.C. 0120, when they stole one of the prototype F90 Gundam F90 units, leading the 13th Autonomous Corps to pursue them back to Mars. There, it was learned that the Mars Zeons had converted Olympus Mons into a gigantic rail cannon, and were planning on bombarding the Earth and destroying the Federation. Thanks to the efforts of the 13th Autonomous, however, the Mars Zeons were defeated and the Olympus Cannon was destroyed.
In Mobile Suit Gundam F91: Formula Report 0122, The Oldsmobile Army eventually invaded Earth in U.C. 0122 under the leadership of Charles Rochester, allying with the Crossbone Vanguard. However, when the Federation started to deploy their down-scaled mobile suits, such as the F71 G-Cannon and the RGM-109 Heavygun, they proved to be very effective against Mars Zeon's larger mobile suits.
- AMS-119 Geara Doga
- MAN-08S Helios
- MS-07B Gouf
- OMAX-01 Grand Zam
- OMAX-03RF RF Adzam
- OMS-09RF RF Dom
- OMS-14RF RF Gelgoog
- OMS-15RF RF Gyan
- OMS-90R Gundam F90
- OMSM-07RF RF Z'Gok
- Sand Angler-class
|Universal Century Nations and Factions|
|Earth Federation Forces | Titans | New Desides | Londo Bell | ECOAS | Phantom Sweep Corps | Federation Survey Service | League Militaire | Man Hunting Attachment|
|Autonomous Republic of Munzo | Principality of Zeon | Axis Zeon | Neo Zeon | Glemy Faction | Republic of Zeon | Delaz Fleet | Mars Zeon/Oldsmobile | ReZeon | Midnight Fenrir Corps | Chimera Corps | Invisible Knights|
|Anti-Earth Federation Movements|
|Anti Earth Union Group | Karaba | Mufti|
|Crossbone Vanguard | Cosmo Babylonia | Jupiter Empire | Jupiter Energy Fleet | Riah Republic | Zanscare Empire/BESPA | Congress of Settlement Nations | Metatron/Zi Zeon|
|Anaheim Electronics | Buch Concern | Colony Public Corporation | Hervic Company | SNRI | Flanagan Institute | Minovsky Physics Society | MIP | Newtype Research Institute | Vist Foundation | Zimmad | Zeonic | List of Universal Century companies|