The following are known Game Genie Codes for Maniac Mansion on Nintendo Entertainment System (NES).

• All Codes Start Out As 0000
  SEXGKASZ
  Note: This includes Edna’s Phone Number (Will show the wrong number in the bathroom), the Safe combination (Won’t be shown correctly in the telescope), the Seckrit Lab inner door (which always starts out as 0000), and the Polices’ Radio number (which the poster won’t show correctly). The ‘secret’ keypad near the ‘Steel Security Door’ has a randomly generated password every time it’s used, so don’t use it.