Cognitive impairment is common in geriatric depression, and depressed individuals with co-morbid cognitive impairment are at increased risk for a number of adverse medical, psychiatric and cognitive outcomes. This review focuses on clinical issues surrounding the co-occurrence of these two conditions within the context of current research. We (1) review the clinical criteria and prevalence of depression, as well as co-morbid cognitive impairment, (2) discuss factors associated with persistent cognitive impairment in depression, including dementia, and (3) review research relevant to the assessment and treatment of cognitive impairment and dementia in the context of depression. We conclude that current research on depression and cognition can inform clinical decisions that reduce the occurrence of adverse outcomes. Clinicians are encouraged to develop proactive approaches for treatment, which may include combinations of pharmacological and psychotherapeutic interventions.