GDI's basic infantry, Rangers are fast and cheap but individually vulnerable, they are best when pitched against other light infantry. However, when used in large groups, they can be devastating to even the mightiest units. Tiberium harms Rangers, like most other unprotected infantry.
G.D.I. Grenadiers are armed with discus shaped explosives which are designed to damage armored units. The ammunition of which the Grenadiers carry is highly explosive so these soldiers very rarely move in large groups.
G.D.I. Engineers are capable of repairing friendly structures, as well as taking complete control over those of an enemy.
After several years of experiments and GloboTech research, GDI have perfected the glorious Rocketeer. These soldiers carry heavy Machine Guns as they soar through the sky, giving them the ability to take out designated targets at great ranges. In the event of anti-aircraft or Incoming storms, GDI Rocketeers will move on foot in order to complete their objectives.
Specially trained GDI Snipers are able to eliminate enemy Infantry at extremely long and safe ranges.
During the First Tiberium War, GDI military officers realized the lack of a powerful but mobile long-range artillery unit that could challenge Nod's Howitzers. While the Multi-Launch Rocket System was being shifted into a more stable platform, it was deemed too slow to be quickly dragged behind frontlines. The training of special Siege Trooper's began; Heavy infantry armed with long-range portable mortars, offering both quick transportation in numbers via APCs and the destructive capacity that of a heavy artillery. Due to the obvious weight of the gunpiece, the Siege Trooper's are enhanced with a mechanic exoskeleton courtesy of GloboTech, offering both protection and additional strength. Such technology is still in its early phases, however, so the Siege Trooper can't move faster than walking pace.
This specially trained Railgun Commando carries a large railgun capable of through just about anything with ease. It is effective against all forms of armour and has no problem ripping through infantry and aircraft alike. As the specially designed Railgun isn't as effective against structures, the Commando carries several C4 charges to plant on buildings and upon detonation, cause their instant destruction. He is one of the best additions to the GDI ever since the rebirth.