Cognitive dysfunction among cancer survivors, commonly referred to as "chemobrain," has gained increased attention in the last decade. Cognitive dysfunction is now well recognized among patients with non-central nervous system cancers. It may be a consequence of the cancer, its treatment, or both. Other common problems among cancer survivors, such as insomnia, pain, depression, and fatigue, may play a role in cognitive performance. Three options to assess cognitive function at present include neuropsychologic testing, functional neuroimaging studies, and subjective evaluations, although no "gold standard" currently exists. Treatment options for survivors with cognitive problems are limited because research in this arena is in its infancy.