Sang-hyun, a priest working for a hospital, selflessly volunteers for a secret vaccine development project intended to eradicate a deadly virus. However, the virus eventually takes over the priest. He nearly dies, but makes a miraculous recovery by an accidental transfusion of vampire blood. He realizes his sole reason for living: the pleasures of the flesh.
- Song Kang-ho as Sang-hyun, a Catholic priest, who volunteers to be a patient of the "Emmanuel Virus," becoming a vampire after receiving blood from unknown origin. He then struggles to deal with his newfound lust for blood.
- Kim Ok-bin as Tae-ju, a young wife of Sang-hyun's childhood friend, fed up with her mundane life while Sang-hyun develops a new love for her.
- Kim Hae-sook as Mrs. Ra, the overly protective mother of Kang-woo.
- Shin Ha-kyun as Kang-woo, Sang-hyun's sick childhood friend and Tae-ju's husband, whom he annoys and abuses according to her.
- Park In-hwan as Priest Roh, a blind priest superior to Sang-hyun, who wishes to see again.
Thirst received generally favorable reviews from critics on its original release; film ranking website Rotten Tomatoes reported that 81% of critics had given the film positive reviews based upon a sample of 114, with an average rating of 6.83/10. The site's critics consensus reads, "The stylish Thirst packs plenty of bloody thrills to satisfy fans of both vampire films and director Chan Wook Park." At Metacritic, which assigns a normalized rating out of 100 to reviews from mainstream critics, the film has received an average score of 73 based on 21 reviews, indicating "generally favorable reviews".
Prominent film critic Roger Ebert awarded Thirst three out of a possible four stars, citing that the director was "today's most successful director of horror films." The website IGN awarded the film three and a half out of five stars and said "Thirst may not be the greatest vampire movie ever made, but Park's willingness to try something different makes it a decidedly fresh take on the genre."
The film won the Jury Prize at the 2009 Cannes Film Festival.
On 3 May, Thirst debuted at #1 at the South Korean Box office and grossed ₩1,174,224,500 the first day and ₩4,369,977,022 for that three-day weekend. More than 2,223,429 tickets were sold nationwide becoming the 9th most attended film of 2009.