Adjustment disorder is a diagnosis given following a significant psychosocial stressor from which an individual has difficulty recovering. The individual's reaction to this event must exceed what would be observed among similar people experiencing the same stressor. Adjustment disorder is associated with suicidal ideation and suicide attempt. However the association between adjustment disorder and completed suicide has yet to be examined. The current study is a population-based case control study examining this association in the population of Denmark aged 15 to 90 years. All suicides in Denmark from 1994 to 2006 were included, resulting in 9,612 cases. For each case, up to 30 controls were matched on gender, exact date of birth, and calendar time, yielding 199,306 controls. Adjustment disorder diagnosis was found in 7.6% of suicide cases and 0.52% of controls. Conditional logistic regression analyses revealed that those diagnosed with adjustment disorder had 12 times the rate of suicide as those without an adjustment disorder diagnosis, after controlling for history of depression diagnosis, marital status, income, and the matched factors.