The 77-year-old actor and his wife, Lauren Shulkind put out a joint statement on Dow's Facebook page Thursday sharing the "very sad news" of his diagnosis but didn't disclose details of the disease.
"Dear Friends & Fans of Tony Dow, I have some very sad news to share with you. Unfortunately, Tony has once again been diagnosed with cancer. He is approaching this reality so bravely, but it is truly heartbreaking," the joint statement read.
USA TODAY reached out to Dow's rep for comment.
The actor and director has been public about previous health struggles. In August he was hospitalized with pneumonia, his agent Frank Bilotta confirmed at the time.
"He was up walking around yesterday and his doctors think he should be able to return home within the week," Bilotta posted on his Facebook.
Dow is best known for his role as big brother Wally Cleaver in "Leave It to Beaver" from 1957 to 1963, and later reprised his role as Wally in a "Beaver" spinoff from 1983 to 1989. He also directed several episodes of 1993's "Babylon 5" along with 1999 episodes of "Crusade" and "Star Trek: Deep Space Nine."
The actor, born Anthony Lee Dow, has starred in an array of television series as a child and was involved in A Minor Consideration, a non-profit foundation to provide support for child actors.
In 2017, Dow reflected on his acting career and celebrated "Leave It To Beaver" 's 60th anniversary in an interview with the Arizona Republic, part of the USA TODAY Network.
“It’s nice to be remembered any way you can, so I have accomplished that,” Dow said at the time. “I’m much more appreciative of the show. I was not unappreciative, but I was always a little rebellious."
Contributing: Jenna Ryu
This article originally appeared on USA TODAY: Tony Dow, 'Leave it to Beaver' actor, reveals cancer diagnosis