Bipolar disorders are prevalent, often severe, and disabling illnesses with elevated lethality largely due to suicide. Suicide rates average ∼1% annually, or perhaps 60 times higher than the international population rate of 0.015% annually. Suicidal acts typically occur early in bipolar disorders and in association with severe depressive or mixed states. The high lethality of suicidal acts in bipolar disorders is suggested by a much lower ratio of attempts:suicide (∼3:1) than in the general population (∼30:1). Risk factors can help to identify patients at increased suicidal risk, but ongoing clinical assessment is essential to limit risk. Empirical short-term interventions to manage acute suicidal risk include close clinical supervision, rapid hospitalization, and electroconvulsive therapy. Remarkably, however, evidence of the long-term effectiveness of most treatments against suicidal behavior is rare. A notable exception is lithium prophylaxis, which is associated with consistent evidence of major (∼80%), sustained relative reductions of risk of suicides and attempts, and lower lethality (increased attempts:suicide ratio). Such benefits are unproved for other treatments commonly used to treat bipolar disorder patients, including anticonvulsants, antipsychotics, antidepressants, and psychosocial interventions. Applying available knowledge systematically, with close and sustained clinical supervision, can enhance management of suicidal risk in bipolar disorders patients.