Monster Farm Online (also known as Monster Rancher Online) is the first game in the Monster Rancher series for the PC, as well as being the first MMORPG in the series. The game is only available in Japanese. The game was originally scheduled for winter 2006, but was postponed to December 21, 2007. Registration and download were closed off again and will reopen November 2009, as the official site's FAQ stated. According to the official website as of August 31, 2010 the game's servers will be going down indefinitely.
Like other games in the series, the main gameplay aspect is raising, and fighting with monsters.
The generating of monsters from real world discs returns. The player can use any disc (even if it's not a disc that would normally work on a PC) to generate a monster.
This time around the player can choose which monster they want when they generate a monster at the shrine when using a real world disc. The disc determines the stats and monster subtype. When the player generates a monster for the first time, it's recorded in their monster book so they can generate it whenever they want.