Although obsessive-compulsive disorder (OCD) has received increasing attention, the study and treatment of OCD in late life has been neglected. The obsessions and compulsions seen with older adults do not appear to differ from the symptoms experienced by other age groups, although developmental issues might influence symptom focus (e.g., memory functioning-related obsessions). Hoarding difficulties might be prevalent in late life, although additional studies are needed. Seniors with OCD can present with comorbid psychiatric disorders, multiple general medical problems, and impaired cognitive functioning, complicating evaluation. There have not been controlled clinical trials of cognitive-behavioral therapy (CBT) for late-life OCD, although initial reports suggest older adults respond to CBT that includes age-related treatment modifications. We illustrate the challenges to assessing and treating older adults with OCD with case examples involving memory-related obsessions and clinical hoarding. The successful strategies used for adapting CBT for the treatment of late-life generalized anxiety disorder might serve as a model for advancing the study and treatment of late-life OCD. (Contains 2 tables and 1 figure.)