BACKGROUND: Rates of suicide among older adults in the United States are higher than that of other age groups. Therefore, it is critically important to deepen understanding of the processes that drive suicide risk among at-risk older patients. To this end, we examined the longitudinal course of suicide ideation in a sample of treatment-seeking depressed adults 60 years of age or older. METHODS: Secondary analyses were conducted with a longitudinal dataset including 343 older adults seeking treatment for depression in the context of a naturalistic treatment setting. Participants completed assessments of depressive symptoms and thoughts of suicide every three months for one year. Multi-level mixed models were used to examine the trajectory of suicide ideation over five waves. RESULTS: Depressive symptoms contributed significantly to change in thoughts of suicide early in treatment for depression. Age-related differences were also observed, such that increasing age was associated with significantly greater reports of suicide ideation. LIMITATIONS: Use of a single measure to ascertain severity of depressive symptoms and thoughts of suicide. CONCLUSIONS: Clinicians should expect to see the most pronounced decrease in thoughts of suicide during the first two months of depression treatment for older adults. Further, clinicians should be especially vigilant to monitor suicide ideation for adults, with increasing vigilance for those at more advanced ages.