Super Mario Bros. is a platform game developed and published by Nintendo in late 1985 for the Nintendo Entertainment System. Super Mario Bros. featured gameplay that changed the way video games were created. It is the first console original in this genre to feature smooth-scrolling levels, which made it a landmark in home video-gaming.

In Super Mario Bros., Italian plumber Mario must save Princess Peach (Princess Toadstool in the US version) of the Mushroom Kingdom from the evil Bowser, king of the Koopas. Mario is aided in his quest by his brother Luigi in two-player mode. In order to save Princess Peach, the Mario Bros. must conquer the eight worlds that comprise the Mushroom Kingdom. Mario (or Luigi) must make his way to the castle in each world and defeat one of the Bowser's evil minions, thereby taking control of that world. In order to reach the castle, however, Mario or Luigi must battle through three "sub-worlds" by either destroying or avoiding Bowser's henchmen. If Mario or Luigi successfully fights his way through the castle and defeats the evil minion, a Mushroom Retainer (later called Toad), is freed. Inside the eighth castle, the Mario Bros. will find Princess Peach.

As of 1999, Super Mario Bros. is the best selling video game of all time, and was largely responsible for the initial success of the Nintendo Entertainment System, as well as ending the two year slump of video game sales in the United States after the video game crash of 1983. It has inspired countless imitators, two direct sequels, and many spinoffs, as well as an entire video game series, and was one of Shigeru Miyamoto's most influential early successes. The game starred the Italian plumber Mario and his brother Luigi. Mario went on to become Nintendo's most well known mascot. The theme music, by Koji Kondo, is recognized worldwide, even by those who have not played the game, and has been considered a representation for video game music in general.

The game was succeeded by a direct sequel in Japan (later retitled Super Mario Bros.: The Lost Levels outside Japan), and by a slight revision of Yume Kōjō: Doki Doki Panic that introduces Mario characters, elsewhere in the world. In both cases, the games are titled Super Mario Bros. 2, causing both games to be re-released in different countries under different titles. There also have been many "alternate" versions of the game, such as All Night Nippon Super Mario Bros., which featured personalities from a famous Japanese radio show, as well as an arcade game. The success of Super Mario Bros. has caused it to be ported to almost every one of Nintendo's major gaming consoles, as well as the NEC PC-8801.