OBJECTIVE: To estimate the frequency of depressive symptoms and selected psychiatric disorders in the Women’s Health Initiative Memory Study (WHIMS) cohort and related them to cognitive syndromes. DESIGN: WHIMS was a randomized, double-blinded, placebo-controlled prevention clinical trial examining whether opposed and unopposed hormone therapy reduced the risk of dementia in healthy postmenopausal women. Participants scoring below a designated cutpoint on a cognitive screener received a comprehensive neuropsychiatric workup and adjudicated outcome of no cognitive impairment, mild cognitive impairment, or probable dementia. PARTICIPANTS: Seven thousand four hundred seventy-nine WHIMS participants between age 65 and 79 years and free of dementia at the time of enrollment in WHIMS. Five hundred twenty-one unique participants contributed complete data required for these analyses. MEASURES: Depressive symptoms were measured with the 15-item Geriatric Depression Scale and the presence of selected psychiatric disorders (major depression, generalized anxiety, and panic and alcohol abuse) was made using the PRIME-MD. RESULTS: The 18% of women had at least one psychiatric disorder with depression being the most common (16%) followed by general anxiety or panic (6%) and alcohol abuse (1%). Depression and the presence of a psychiatric disorder were associated with impaired cognitive status. Participants having a psychiatric disorder were more than twice as likely to be diagnosed with cognitive impairment as those with no psychiatric disorder (odds ratio = 2.06, 95% confidence interval = 1.17-3.60). Older age, white race, and diabetes were also associated with cognitive impairment. CONCLUSION: The frequency of a psychiatric disorder is associated with poorer cognitive functioning among older women enrolled in WHIMS. That approximately one in five women had a probable psychiatric disorder, most typically depression, highlights the need for greater detection and treatment efforts in this population.