Demographic, diagnostic, crime scene, psycholegal, and legal outcome data were obtained for 68 cases drawn primarily from Southern California. Parricide was defined as the murder of a father, mother, stepfather, stepmother, adoptive parent, or both parents. Clinical archive data were collected from medical examiner case files and forensic reports. Results indicated a 34- percent success rate among defendants who used an insanity defense. Significant differences were found between parricide and attempted parricide in terms of prior psychiatric and violent criminal histories. Findings clearly demonstrated that parricide and attempted parricide cases were not homogeneous in terms of premorbid characteristics, crime scene data, and legal outcomes. Data suggested that the 68 cases fell primarily into one of two groups, severely mentally ill and antisocial offenders. No significant differences between parricide and attempted parricide cases were observed with respect to age, gender, race, marital status, education, employment background, military history, and pre-offense living situation. Parricide subjects used firearms, knives, and bare hands in similar proportions, while attempted parricide subjects primarily used knives. In terms of crime scene data, gender differences were noted in the choice of victim. Male perpetrators were more likely to offend against their mothers or both parents, while female perpetrators only chose their mothers. In terms of judicial proceedings, a 34-percent success rate was observed among defendants who used an insanity defense. The archive data list used in the study is appended. 28 references