Objective: This study aimed to investigate the factors associated with parricide in patients with schizophrenia who committed homicide. Method: Among patients with schizophrenia who were in the National Institute of Forensic Psychiatry between November and December 2007, 88 patients who committed homicides were enrolled; 59 had committed parricide, and 29 had killed strangers. Medical charts, written expert opinions, written records of police or prosecutors, and court decisions were reviewed. Direct interviews with patients were also conducted. Results: Significant factors associated with parricide among homicidal patients with schizophrenia were living with the victim, female sex of the victim, and offense-provoking events including scolding, threatening forced hospitalisation, and forcing medication on the patient before the homicide. Capgras syndrome was present at a significantly higher rate in the parricide group than in the stranger group. Drug compliance at the time of the offence was low in both groups. Conclusions: Untreated psychotic symptoms such as Capgras syndrome, living with elderly parents, especially mothers, and conflicts caused by victims' scolding, threatening forced hospitalisation, and forcing medication on the patients are associated with parricide among homicide offenders with schizophrenia.