Argentum Online is a 1999 Argentinian MMORPG video game. It is available on Microsoft Windows and developed by Pablo Márquez in the city of La Plata. It has the distinction of being the first MMORPG developed in Argentina. A sequel entitled Argentum 2 was at one point in development.

The game has had a life outside of the fictional universe, one of the title's gamemasters noted "The fact that the Argentum community has transcended the barrier of pure fiction is for most of the players one of the most positive characteristics of the game. One day the idea of having dinner arose, to meet us all."

The developers and fans worked together to create variants and mods of the game, by 2001 four different versions had been made.

The game's source code was released in 2003 under the GNU GPL license and can be downloaded from SourceForge.

La Nación described it as a "local pioneer" of the RPG genre. Página 12 suggested that the game is an "anarchic" game with no owner and instead a "game of the people".

Argentum Online is an online multiplayer role playing game which takes place in a medieval fantasy world. The world is known as Argentum, it's populated by all sorts of creatures: evil and good. Players can create their own characters, choosing among five races (Elf, Human, Gnome, Dark Elf, Dwarf) and up to 20 different professions (fighter, assassin, blacksmith, carpenter, pirate, etc).