I have undertaken in this paper to explore the traumatic effects of ongoing interpersonal violence on the developmental process of a 3¹/₂-year-old boy. The clinical material is based on my psychoanalytic five times weekly treatment of Eric over a period of three years. His external environment, including the violent aspects of his family's life, is clarified. The supportive work which attempted to bring about environmental change is outlined. The lasting effects of the violence on Eric's personality and development are estimated, and the possible value to him of his psychoanalytic treatment is assessed.