Efforts to identify clinical risk factors for complete suicide through the follow-up of depressed patients have yielded relatively few robust predictors. Those identified by at least three studies are (in order of decreasing frequency) suicidal plans/attempts, male sex, being single or living alone, inpatient status, and hopelessness. Because the best established of these predictors has only modest sensitivity and specificity, the need for other robust tools is clear. A rich body of research has identified two biological risk factors for suicide in depressive disorder: hypothalamicpituitary-adrenal axis hyperactivity and deficits in serotonin function. Moreover, there is now considerable evidence that the dexamethasone suppression test and measures of serum cholesterol concentrations, respectively, may provide a clinically useful reflection of these two mechanisms. Observations that these measures appear to be additive, both with each other and with other clinical risk factors, indicate that a substantial improvement in the clinician's ability to assess suicide risk is possible.