Depression and dementia are commonly concurrent and are both associated with increased mortality among older people. However, little is known about whether home-dwelling patients newly diagnosed with mild dementia coexisting with depressive symptoms have excess mortality. We conducted a post hoc analysis based on data from the Danish Alzheimer's Intervention Study of 330 individuals who were diagnosed with mild dementia within the past 12 months. Thirty-four patients were identified with major depressive symptoms (MD-S) at baseline. During the 3-year follow-up period, 56 patients died, and, among them, 12 were with MD-S at baseline. Multivariable analysis adjusting for the potential confounders (age, sex, smoking status, alcohol consumption, education, BMI, household status, MMSE, CCI, QoL-AD, NPIQ, ADSC-ADL, medication, and RCT allocation) showed that patients with MD-S had a 2.5-fold higher mortality as compared to the patients without or with only few depressive symptoms. Our result revealed that depression is possibly associated with increased mortality in patients with mild dementia. Given that depression is treatable, screening for depression and treatment of depression can be important already in the earliest stage of dementia to reduce mortality.