Call of Duty: World at War's Map Pack 1 has been downloaded over one million times within its first week on sale for Xbox 360 and PlayStation 3, according to Activision.
Treyarch's downloadable content features four maps and is available on Xbox Live Marketplace for 800 Microsoft Points and on the PlayStation Store for USD 9.99.
"I'm proud that the team at Treyarch delivered an experience that so many people are enjoying," said Mark Lamia, studio head for Treyarch.
"We're excited that the success of Call of Duty: World at War Map Pack 1 will continue to drive the popularity of the game's Nazi Zombie mode, competitive multiplayer and chart-breaking success online."
Maria Stipp, Activision's EVP and GM of owned properties, added: "The success of Call of Duty: World at War Map Pack 1 speaks to Treyarch and Activision's ability to provide fans with quality content during a time when people want to get the most out of their Call of Duty experience."