Patients with involution melancholia had an average annual crude death rate of 132.4 per 1000 exposures. This is almost twice the rate for patients with manic-depressive psychoses, and four times the rate for patients with dementia præcox. It is the highest rate of any of the functional group of psychoses. On the basis of standardized death rates, patients with involution melancholia had a death rate in excess of that of the general population in the ratio of 6.2 to 1. Among males and females the corresponding ratios were 6.2 to 1 and 6.8 to 1, respectively. Males have higher death rates than females, though the difference is not significant with respect to the probable error.Diseases of the heart constitute the leading cause of death, being responsible for almost 40 per cent of all the deaths. The death rate from these diseases is almost eight times the corresponding rate in the general population, when both are corrected for age. Pneumonia was responsible for only a third as many deaths as diseases of the heart. Tuberculosis ranked third as a cause of death. It is noteworthy, however, that the death rate from tuberculosis exceeded that of patients with dementia præcox.