A statistical analysis of nine hundred forty-seven patients with psychoneurotic or psychosomatic disorders revealed a greater incidence of maternal bereavement before the age of five years than is found in the general population. The loss of the mother occurs more frequently in the history of female psychoneurotics than in males. The critical age for the time of the maternal loss with this group of girls is from birth to two years. There is no apparent correlation between paternal bereavement and the incidence of later neurotic disorder. The authors add, however, that since eighty-five percent of the cases in this series had not lost their mothers prior to their twenty-first birthdays, this study focuses on only a single factor in psychoneurotic illness.