World 1-4 is the fifth level of World 1, and subsequently, of New Super Mario Bros. It introduces the Mini Mushroom.
This level is a grassy meadow, much like World 1-1. The first ? Block (which is on the ground, and not floating, unlike most ? Blocks) contains either a Super Mushroom or Fire Flower, depending on Mario's form. A ? Block containing a Mini Mushroom is later found in the level. The Mini-Mushroom can be used to travel into a small pipe nearby that leads to the first Star Coin. A wall made up of bricks and cement blocks are blocking a Pipe. The wall is shaped in such a way that it's possible to throw a Koopa Shell on it, which will break all of the Blocks and will eventually allow the player to enter it. Alternatively, the player could use a Mega Mushroom to break the block wall. The pipe leads to a cave that contains a Star Coin that is reached by using a P Switch that turns every brick into a coin and vice-versa. The third Star Coin is found in a small gap just before the level's pole that is only accessible by running through as Mini Mario, Shell Mario, or Mario without a Super Mushroom, or by sliding down the slope and through the gap in any form.
- Star Coin 1 - The Mini Mushroom in the ? Block can be used to enter the small pipe on the left. The Star Coin is found in plain sight.
- Star Coin 2 - Near a mass of blocks is a pipe blocked by a brick. The player should break it and find the hidden P Switch to turn the coins into blocks to make steps for the Star Coin. Only Super Mario, Fire Mario, and Shell Mario can reach it.
- Star Coin 3 - The third Star Coin is found in a small gap just before the level's pole that is only accessible by Mini Mario, Small Mario, Shell Mario, or by sliding down the nearby slope.