The following are known Action Replay Codes for Madagascar on Nintendo Game Boy Advance (GBA).
These codes were also known as GameShark Codes and in most cases will work on both devices.

These codes are for the U.S. version of the game.

Master Code – Must Be On
3c73e412
87c1d81c
c3249687
484a2341

Infinite Health
27ee8d09
9a304f49

Infinite Time
bc395ff2
61cc9a84