A Star Coin is an item that can be found in the game New Super Mario Bros. for the Nintendo DS and New Super Mario Bros. Wii for the Wii. These items are an enlarged coin with a star on it. There are three star coins coins in each level. In all, there are 240 coins to be found, making the game have more replayability.
When you have 5 Star Coins, you can use them to open Star Gates that block paths leading to Toad Houses or secret levels in the game. The player can also save your game when you open them. It is advised that the player only open these gates when you need to save your game, don't just spend coins because they have them. After Mario/Luigi conquers Bowser's Castle, the player can buy touch screen wallpapers for 20 Star Coins. A star will appear next to your file when you have collected and spent all 240 coins on gates and wallpapers.