OBJECTIVE: Although mental health conditions are risk factors for suicide, limited data are available on suicide mortality associated with specific mental health conditions in the U.S. population. This study aimed to fill this gap. METHODS: This study used a case-control design. Patients in the case group were those who died by suicide between 2000 and 2013 and who were patients in eight health care systems in the Mental Health Research Network (N=2,674). Each was matched with 100 general population patients from the same system (N=267,400). Diagnostic codes for five mental health conditions in the year before death were obtained from medical records: anxiety disorders, attention deficit-hyperactivity disorder (ADHD), bipolar disorder, depressive disorders, and schizophrenia spectrum disorder. RESULTS: Among patients in the case group, 51.3% had a recorded psychiatric diagnosis in the year before death, compared with 12.7% of control group patients. Risk of suicide mortality was highest among those with schizophrenia spectrum disorder, after adjustment for age and sociodemographic characteristics (adjusted odds ratio [AOR]=15.0) followed by bipolar disorder (AOR=13.2), depressive disorders (AOR=7.2), anxiety disorders (AOR=5.8), and ADHD (AOR=2.4). The risk of suicide death among those with a diagnosed bipolar disorder was higher in women than men. CONCLUSIONS: Half of those who died by suicide had at least one diagnosed mental health condition in the year before death, and most mental health conditions were associated with an increased risk of suicide. Findings suggest the importance of suicide screening and providing an approach to improve awareness of mental health conditions.