Pain is one of the most common and feared symptoms associated with cancer. It occurs in 20% to 50% of patients with newly diagnosed malignancies, 33% of patients during the treatment of their disease, and in 75% to 90% of those with advanced cancer. Nearly three-quarters of all patients with cancer report moderate to severe pain at some time during their illness. The importance of this symptom and the availability of excellent analgesic therapies make it imperative that health care providers be skillful at evaluating and treating cancer pain. This article presents in detail state-of-the-art management of pain in patients with cancer.