Oru CBI Diary Kurippu (transl. A CBI diary entry) is a 1988 Indian Malayalam-language mystery thriller film directed by K. Madhu, written by S. N. Swamy, and starring Mammootty, Suresh Gopi, Jagathy Sreekumar, Mukesh, and Sukumaran. The lead character, CBI officer Sethurama Iyer is inspired by a police officer named Radha Vinod Raju, Jammu and Kashmir cadre IPS Officer who in 2009 was appointed as the first chief of India's National Investigation Agency. It was the highest grossing Malayalam film at that time. Considered one of the best crime thrillers in Malayalam, it eventually developed a cult following. This is the first instalment in the CBI film series featuring Mammootty as Sethurama Iyer.

It was produced by M. Mani under the banner Sunitha Productions. Sequels to the film are Jagratha (1989), Sethurama Iyer CBI (2004), Nerariyan CBI (2005), and CBI 5: The Brain (2022). The film was remade in Telugu as Nyayam Kosam with Rajasekhar and in Hindi as Police Public with Raaj Kumar. Oru CBI Diary Kuripp ran for a whole year (365 days) in Tamil Nadu at a time when Malayalam films did not find much of an audience in the neighbouring states.