To determine the prevalence of major depression in cancer patients and assess the usefulness of the dexamethasone suppression test (DST) and the thyrotropin-releasing hormone (TRH) stimulation test for diagnosing major depression in these patients, the authors studied 83 women hospitalized for gynecological cancer. Nineteen (23%) had major depression according to DSM-III criteria. The sensitivity and specificity of the DST were 40% and 88%, respectively. No relationship between DST and TRH test results was found. These findings indicate a high prevalence of depression in cancer patients, but further research on these tests in cancer patients is needed; their routine use with cancer patients is premature at this time.