Markedly elevated circulating concentrations of 17-hydroxycorticosteriods (17-OHCS) have been found by a number of workers1-6in patients with terminal illnesses. However, little is known concerning factors which may influence responsiveness of the pituitary-adrenal system to impending death. The purpose of this communication is to present observations concerning the relationship of such factors as age, chronicity of illness, nature of the disease process, mode of death, and previous corticoid therapy to plasma concentrations of 17-OHCS at death in human subjects. Methods Sixty-four patients ranging in age from ½ hour to 90 years were utilized in this study. The new-born infants were full-term, except as indicated in Table 1. Blood samples were obtained by cardiac puncture, usually within 5 minutes and in all cases within 20 minutes after death. In addition, serial blood specimens were obtained prior to death from six patients with craniocerebral trauma. Plasmas were separated by centrifugation and