The network said the ratings for Sunday's show were the strongest for any drama on basic cable history.
A combined 11 million viewers tuned in for the 9 p.m., 10:30 p.m. and 12:30 a.m. airings.
"'The Walking Dead' is one of those rare television programs that reaches both a core genre fan as well as broad audiences simply looking for a great, character-based story. We're so proud of and grateful for the amazing team on both sides of the camera who works so hard and is so committed to making this a unique programming event," Charlie Collier, AMC's president, said in a statement Monday. "That 'The Walking Dead' is now the most watched drama in the history of basic cable is staggering, just like our zombies."
Set after a zombie apocalypse, the series follows a group of survivors, led by police officer Rick Grimes, who travel in search of a safe and secure home. Andrew Lincoln plays Grimes.