John Bowlby's influential 1951 World Health Organization monograph, Maternal Care and Mental Health, pointed to a causal relationship between loss of maternal care and disturbed personality development, and had a profound effect on psychiatrists' thinking about antisocial behavior in particular, and character formation in general. More recently, psychiatric investigators have been increasingly interested in the effects of a child separation from his father. This has been stimulated by sociological concerns for one-parent, fatherless families (Adams, 1973) and by our realizing how historically neglected has been the paternal role in theories of child development. Herzog and Sudia (1971) have recently compiled an extensive bibliography of the fatherless family. Numerous clinical studies of loss of the father, through death (Nagera, 1970; Wolfenstein, 1966; Bonnard, 1964), suicide (Cain and Fast 1966), divorce (McDermott, 1970), military service (Crumley and Blumenthal, 1973), occupations (Rosenfeld et al., 1973), desertion (Thomes, 1968), and mental hospitalization (Schiff, 1965), have all reported various adverse effects, particularly on male children. It has been difficult, however, to sort out the effects of the loss itself from more general prevailing and prior family relationships. My interest in this subject was quickened when I began to see boys brought to a neighborhood clinic for aggressive and antisocial behavior soon after their fathers were imprisoned. I was impressed by the lack of reports in the literature on this form of father separation. I am presenting here my clinical observations of six families seen over a three-year period as part of a general child psychiatric experience at a comprehensive neighborhood health center sponsored by the Massachusetts General Hospital in Boston. Although there are obvious selection biases that limit generalization when families referred to psychiatrists are the only source of information, it seems a useful place to begin an examination of the consequences for children of father-separation as a result of imprisonment.