Abstract: A case of infanticide committed by a 37-year-old married man, the father of three sons, is reported. Clinically depressed since adolescence, and also diagnosed with obsessive-compulsive disorder and a dependent personality, the subject began to worry about killing someone a decade before the homicide. Increasingly disabled by his major depression, unable to work, and confined in his home, the idea that his only recourse was to kill one of his sons became fixed and frequent. Following his fourth psychiatric hospitalization, he took his 13-month-old son home from day care and drowned him in the bathtub. He then called the police and reported his crime. This sudden act of intentional killing was followed by a period of emotional relief and calmness, clearly illustrating the three stages of chronic catathymic homicide.