Bulgasal: Immortal Souls (Korean: 불가살) is a South Korean television series starring Lee Jin-wook, Kwon Nara, Lee Joon, Gong Seung-yeon, Jung Jin-young, Park Myung-shin, and Kim Woo-seok. It is led by director Jang Young-woo, and the screenplay is written by husband-and-wife team Kwon So-ra and Seo Jae-won. It aired on tvN from December 18, 2021 to February 6, 2022. It is also available for streaming on Netflix.

The series tells the story of a woman who remembers her past lives by repeating death and reincarnation for 600 years, and a man who cannot kill nor be killed and has lived for the past 600 years as a Bulgasal—a mythical creature that feeds off human blood and is cursed with immortality.

The lead role was first offered to Won Bin, but the actor ultimately refused.

On December 17, 2020, it was reported that Lee Jin-wook was being cast for the series and was positively considering his appearance. The actor and director Jang Young-woo previously worked together in the 2020 series Sweet Home. In February 2021, actors Lee Joon, Kwon Nara and Jung Jin-young also received casting offer. Line-up for the lead stars consisting of Lee Jin-wook, Kwon Nara, Lee Joon, Gong Seung-yeon, Jung Jin-young, Park Myung-shin and Kim Woo-seok was finally confirmed on March 17.

Bulgasal: Immortal Souls was initially scheduled for release in 2022. In November 2021, it was confirmed that the series would premiere on December 18.