The show returns in June for its fourth series and the Beeb has already commissioned a fifth run in 2019.
But Aidan - who plays the title character - has suggested they'll be the last episodes.
"It’s been big for us all and it’ll always be a special thing but things naturally do come to an end and I think we’ve done really well with Winston’s books and I hope he’d be really proud," he said. “But it’s nice when things naturally come to an end, you don’t want things to go on really long.
“I think next year might be the last one, certainly for a while.”
He added: “We may come back, who knows. There’s a huge gap in the books, about 15 years.
“I wouldn’t age up, I’d come back in 10 years. I’d revisit it the right way, I’m not putting grey in my hair or anything like that.”
Meanwhile, Poldark has found itself the latest BBC One show caught up in a 'pay gap scandal'.
It's after Aidan's co-star Eleanor Tomlinson told the July issue of Red magazine that she hoped the pair were on equal pay.
Asked if they were paid the same, Eleanor said: “My guess is no. And while at the beginning that might have been ok - he was a bigger star than me - now I don’t think so. We’re equal leads of the show, so I’d be pretty upset if the gap hadn’t closed.”
A spokesperson confirmed: “Whilst we can’t and won’t disclose the details, we do pay Aidan Turner more for playing Ross Poldark as throughout all series Ross has significantly more screen time than any other character.”