One hundred and forty-five patients with primary depressive illness admitted to a university hospital between 1966 and 1970 were followed up an average of 15 years later. Adequate data were obtained on 133 (92%) of the 145. During the follow-up period, 7% of the 133 had suicided, 12% had remained incapacitated by illness and only 20% had remained continuously well. Patients for whom the index admission was not their first were especially likely to be readmitted during the follow-up period. Patients with endogenous depression, none of whom developed schizophrenia during the follow-up period, were more likely to need readmission than patients with an index diagnosis of neurotic depression. In all other respects the prognosis for the two types of depression was the same, with considerable morbidity evident in both.