"Survivor" host Jeff Probst lost a family member ... his brother, Scott Probst, is dead.

Scott's death was announced Monday by their brother, Brent ... in a social media post, he says ... "Some sad news, our brother Scott is no longer with us. He was a great brother, son and friend. I will miss him so much ❤️ I’m so sad he is gone."

The cause and manner of death is unclear.

Jeff hosted "Survivor" since 2000 and Scott has credits on a handful of episodes ... as a camera assistant and an art assistant.

It's the second death in Jeff's immediate family in less than two years ... his mother, Barb Probst, died back in November 2024 and the reality survival competition show honored her with a tribute card in a season 47 episode.

Scott was 58.

RIP