Gradius III and IV is a compilation game combining ports of the arcade versions of Gradius III (1989) and Gradius IV (1999). It was released in Japan on April 13, 2000, and North America and Europe in November 2000. The game was a launch title for the PS2 in PAL regions.

The overall gameplay is similar to the arcade versions, but included with a stage select and option menu. The option menu is similar to the configuration menus in the arcade versions, except that the ability to save and load high scores and adjust the screen has been added. For Gradius III, the option to change the amount of lag has been added because the PS2 processor is much faster than the arcade processor and for Gradius IV, the option to change sound (stereo/mono) and screen size (PCB/full-size) has been added.