Most prospective studies of HPA axis have found that non-suppressors in the dexamethasone suppression test (DST) are more likely to commit suicide during the follow-up. Attempted suicide is a strong clinical predictor of suicide. The aim of this study was to assess the predictive value of DST for suicide in a group of depressed inpatients with and without an index suicide attempt. Historical cohort of 382 psychiatric inpatients with mood disorder admitted to the department of Psychiatry at the Karolinska University Hospital between 1980 and 2000 were submitted to the DST and followed up for causes of death. During the follow-up (mean 18 years), 36 suicides (9.4%) occurred, 20 of these were non-suppressors and 16 were suppressors. There was no statistically significant difference in suicide risk between the suppressors and non-suppressors for the sample as a whole. An index suicide attempt predicted suicide. In suicide attempters with mood disorder, the non-suppressor status was significantly associated with suicide indicating that HPA axis hyperactivity is a risk factor for suicide in this group. The dexamethasone suppression test may be a useful predictor within this population.