The increased risk of suicide in the period after discharge from a psychiatric hospital is a well-recognized and serious problem. The aim of this study was to establish the risk factors for suicide in the year after discharge from psychiatric hospitals and their usefulness in categorizing patients as high or low risk for suicide in the year following discharge. A systematic meta-analysis of controlled studies of suicide within a year of discharge from psychiatric hospitals. There was a moderately strong association between both a history of self-harm (OR = 3.15) and depressive symptoms (OR = 2.70) and post-discharge suicide. Factors weakly associated with post-discharge suicide were reports of suicidal ideas (OR = 2.47), an unplanned discharge (OR = 2.44), recent social difficulty (OR = 2.23), a diagnosis of major depression (OR = 1.91) and male sex (OR = 1.58). Patients who had less contact with services after discharge were significantly less likely to commit suicide (OR = 0.69). High risk patients were more likely to commit suicide than other discharged patients, but the strength of this association was not much greater than the association with some individual risk factors (OR = 3.94, sensitivity = 0.40, specificity = 0.87). No factor, or combination of factors, was strongly associated with suicide in the year after discharge. About 3% of patients categorized as being at high risk can be expected to commit suicide in the year after discharge. However, about 60% of the patients who commit suicide are likely to be categorized as low risk. Risk categorization is of no value in attempts to decrease the numbers of patients who will commit suicide after discharge.