Bio Hunter (バイオ・ハンター, Baio Hantā) is a Japanese manga series authored by Fujihiko Hosono. It tells the story about two molecular biologists, Koshigaya and Komada who take on humans with strange viruses that make them less human and more demonic. It was serialized in the Scola manga magazine Comic Burger.The manga was also adapted into an hour-long single-episode anime OVA, produced by Madhouse Studios and Toei Video, directed by Yuzo Sato and scripted by Yoshiaki Kawajiri. It was distributed throughout the United States and Canada by Urban Vision. The English dub is distributed by MVM Films in the United Kingdom and Madman Entertainment in Australia and New Zealand.

The movie has similar animation and dark urban fantasy themes that Kawajiri worked on before and after Bio Hunter, such as Ninja Scroll, Devilman OVA, X/1999 anime TV series, and Gungrave. Kawajiri, Yamamoto and Maruyama worked again as a team between 1997 and 2000 in making the Madhouse's Vampire Hunter D: Bloodlust.