This report covers part of an investigation (Perris: 1966) concerned with a possible differential diagnosis between bipolar (manic-depressive) and unipolar recurrent depressive psychoses according to the classification of Leonhard (1959) and deals with a study of mortality rate and the incidence of suicide. Some details will also be given concerning the lifecycles of patients who died during the period of investigation.Investigations into mortality in depressive psychotics have appeared in the litterature: Pollock (1931), Malzberg (1934), Essen-Moller [1935), Schultz (1 949), Stenstedt (1 952, 1959), Kinkelin (1 954), Astrup e t al. (1959).The mortality in the series combining both bipolar and unipolar depressive patients has been found to be higher than in the normal population. Pollock Cop. cit.) found that 65 per cent of his large series of ))manicdepressive)) patients died before the age of 50. Stenstedt (1952) reports that the remaining mean expectation of life in manic-depressive patients is about 15 per cent lower than in the normal population. Astrup e t al. (op. cit.) found that the mortality in a group of treated manic-depressive patients was higher in males. This finding is confirmed by Lewis (1964) who states that the crude death rate in men is nine times and in women six times the corresponding rate for persons aged 16 or more in the general population.