OBJECTIVE Cognitive impairment has been associated with late-life suicidal behavior. Without longitudinal data it is unclear whether these are transient features of a depressive state or stable impairments. We examined longitudinally the course of cognitive impairment in older adults with depression and a history of suicide attempt. METHODS We investigated the persistence of cognitive impairment over time in 198 depressed older adults (age >60); 91 suicide attempters, 39 depressed individuals with suicidal ideation (ideators), and 68 non-suicidal depressed adults assessed over a 2-year period at four time points. We used linear mixed effects modeling to examine group differences in trajectories of cognitive decline over 2 years, using the Mini-Mental State Examination (MMSE), Mattis Dementia Rating Scale (DRS), and Executive Interview (EXIT). RESULTS Over the 2-year period, suicide attempters performed significantly worse than both suicide ideators and non-suicidal depressed older adults on the MMSE (mean difference: from ideators: -0.88, p = 0.02; from non-suicidal depressed: -1.52, p < 0.01), while on the EXIT and DRS, suicide attempters performed significantly worse than non-suicidal depressed older adults (mean difference: in EXIT: -1.75, p = 0.01; in DRS: 3.04, p < 0.01; in MMSE: 1.15, p < 0.01). Cognitive impairment in suicide attempters partly resolved, as indicated by a group × time interaction on the DRS (p = 0.039), but not the EXIT (p = 0.58) or the MMSE (p = 0.08). CONCLUSIONS Cognitive impairment in late-life suicidal behavior appears to involve both a stable and a state-related component.