This review includes research findings from sleep-related studies on specific types of cancers, on specific types of treatment protocols, and on persons with end-stage cancer regardless of treatment protocol. Since treatment protocols have evolved in the past decade, literature since 1990 is emphasized. We conclude that researchers should design studies that attend to prior sleep history, gender, type of cancer and treatment modalities, and the specific type of sleep problems experienced over the course of diagnosis, treatment, and recovery. More research is also needed to understand sleep problems in children with cancer and sleep problems in family caregivers. Research is also needed on effective pharmacological and non-pharmacological interventions. Daytime functioning, daytime sleepiness, and altered circadian rhythms should be considered salient outcomes in addition to severity of cancer-related fatigue. Clinicians should consider whether a patient's sleep problem has been chronic and unrelated to cancer, or precipitated by diagnosis and treatment. The specific type of sleep problem should be ascertained so that appropriate interventions can be prescribed. Appropriate interventions can include either pharmacological medication or behavioral strategies, and each has the potential to promote restorative sleep and thereby improve the patient's quality of life, daytime functioning, and well-being.