The Walking Dead Season 5 opener has been watched by 17.3 million people, breaking cable viewing records.
It marks the biggest cable audience for a non-sports program in the US, according to television viewing figures tracking company Nielsen.
The Walking Dead, which stars British actor Andrew Lincoln, held the previous record of 16.1 million for its fourth season debut last year.
The end of the series also set a new benchmark for a finale with 15.7 million.
Sunday’s return to the air also triumphed in the valuable 18-49 age range with 11 million viewers. Its nearest scripted rival was popular comedy The Big Bang Theory, which pulled in 6.9 million people in that key demographic.
Variety reported that the AMC show also reached record levels for the number of people obtaining the show illegally, with piracy tracking firm Excipio logging 1.27 million downloads in the first 24 hours after transmission.
But the level of piracy for TV series Game of Thrones pushes The Walking Dead into second place, with its fourth series premiere registering 1.86 million illicit downloads.
It added that Fox has rushed the show to some 125 markets around the world in a bid to thwart piracy.
The hit show tracks the fortunes of sheriff Rick Grimes – played by Andrew Lincoln – as he attempts to survive flesh-eating zombies.