Abstract: Asthma and suicide attempts are leading causes of morbidity and mortality among adults in the United States. The objective of this study was to investigate the relationship between asthma and suicidal ideation and suicide attempt among adults in the United States, and to examine whether timing of asthma, mood disorders, poverty, allergies, cigarette smoking and sex differences confound these relationships. Data were drawn from the Third National Health and Nutrition Examination Survey (NHANES III), a representative sample of adults (N = 6584) in the United States. Logistic regression analyses were used to examine the relationships between current and former asthma and suicidal ideation and suicide attempt, adjusting for demographics, poverty, smoking, allergies and mood disorders. Current asthma is significantly associated with an increased likelihood of suicidal ideation (OR: 1.77, CI: 1.11, 2.84) and suicide attempt (OR: 3.26, CI: 1.97, 5.39), after adjusting for mood disorders, smoking, poverty and demographics. There does not appear to be a significant relationship between former asthma and suicidal ideation or suicide attempt. These findings confirm and extend previous evidence by showing that the link between asthma and suicide-related outcomes is evident among adults in a representative sample and that this relationship persists after adjusting for a range of variables. This study may provide an empiric foundation for including asthma in the clinical assessment of suicide risk.