The Atari 800 represented Atari's entry into the home computer market, hoping to capitalize on the success of their 2600 game console. The 800 had very powerful graphics capabilities - it was capable of displaying 128 colors (later models, with an upgraded video chip, could display 256 colors).

One of the strengths of the 800 was the fact that it was easily expandable. The case opened easily, revealing four expansion slots. One was reserved for the OS card, while the others were designed for RAM cards (although some third-party companies developed RAM disks and modem interface cards).

The 800's case was intentionally designed to resemble a typewriter. The designers wanted to give the machine a familar, friendly appearance.

The Atari 800 remained in production until 1982, when it was replaced by the 1200XL. While it boasted 64 KB of RAM, it also had no expansion slots and only 2 controller ports. The 1200XL was a failure, and actually caused an increase sales of the 800 as people rushed to buy them before they disappeared.