Of 55 children admitted to a children's psychiatric service, 21 were homicidally aggressive. Psychiatric symptoms and diagnoses did not distinguish these children from the nonhomicidal children. However, the homicidally aggressive children were significantly more likely to have a father who behaves violently, often homicidally; have had a seizure; have attempted suicide; and have a mother who has been hospitalized for a psychiatric disorder. A stepwise multiple regression analysis, using homicidal aggression and its absence as the dependent variables, revealed that these four factors together accounted for 57.5 percent of the variance. The father's violence toward the mother accounted for 27.5 percent of the variance, seizures for 15.7 percent, suicidal behavior for 9.2 percent, and the mother's admission to a psychiatric hospital for 6.9 percent. The most significant factor contributing to violence seems to have been experiential, namely, having a violent father. A violent father furnishes a model for behavior. When directed toward the child, his violence often causes central nervous system vulnerability to impulsiveness. Finally, witnessing and being the victim of irrational violence engenders a kind of rage and frustration that expresses itself as either suicidal or homicidal behavior. Tabular data and 20 references are included.