The aim of this study is to determine in a Japanese sample whether or not the permanent loss of a parent by death or separation in childhood is aetiologically associated with unipolar major depressive disorder (according to RDC). We compared the incidence of parental loss before 17 years of age by death or separation between 122 depressed inpatients and 94 non- and never-depressed medical controls. Early maternal death was found to be significantly more common in the depressives than in the controls. Separation from either parent also showed a trend towards an increased incidence in the depressive group. No significant difference in the incidence of early paternal death was found.