Power-up items are the backbone of Mario's arsenal, transforming him and granting crucial abilities. Knowing their effects and when to use them is vital:

- Super Mushroom: The most basic power-up, transforming Small Mario into Super Mario. This allows Mario to take one hit without losing a life. Always try to maintain this form.
- Fire Flower: Transforms Super Mario into Fire Mario, allowing him to shoot fireballs. Fireballs bounce along the ground and can defeat most enemies, including some that are otherwise invulnerable to stomping.
- Cape Feather: Transforms Super Mario into Cape Mario. This is arguably the most powerful power-up, granting flight, gliding, and a spin attack. Mastering the Cape Feather is essential for finding many secrets and shortcuts. To fly, run to full speed, jump, and hold A. To glide, hold A after a jump. To spin, press Y or X while airborne.
- Starman: Grants temporary invincibility. While invincible, Mario can run through most enemies without taking damage. This is excellent for clearing crowded areas or rushing through dangerous sections.
- 1-Up Mushroom: Grants an extra life. These are often found in hidden blocks or as rewards for collecting 100 coins or five Dragon Coins.
Always try to keep a spare power-up in your item box for emergencies. The Cape Feather is often the most valuable to store.