Its a different format altogether: although a standalone player may accept both, a DVD-R drive will not accept a DVD+R disc, and vice-versa. If you are asking the question because you wonder which type of burner to buy, the basic criteria are: 1) DVD-R is currently more widely supported by standalones; and 2) blank DVD+R discs are more expensive than -R discs. This could all change (wonderfull thing about tech) or they could both be outdated soon (blueray anyone?). But that's the lay of the land right now.