Worldwide, the prevalence of cancer is rising and so too is the number of patients who survive their cancer for many years thanks to the therapeutic successes of modern oncology. One of the most frequent and disabling symptoms of cancer is pain. In addition to the pain caused by the cancer, cancer treatment may also lead to chronic pain. Despite its importance, chronic cancer-related pain is not represented in the current International Classification of Diseases (ICD-10). This article describes the new classification of chronic cancer-related pain for ICD-11. Chronic cancer-related pain is defined as chronic pain caused by the primary cancer itself or metastases (chronic cancer pain) or its treatment (chronic postcancer treatment pain). It should be distinguished from pain caused by comorbid disease. Pain management regimens for terminally ill cancer patients have been elaborated by the World Health Organization and other international bodies. An important clinical challenge is the longer term pain management in cancer patients and cancer survivors, where chronic pain from cancer, its treatment, and unrelated causes may be concurrent. This article describes how a new classification of chronic cancer-related pain in ICD-11 is intended to help develop more individualized management plans for these patients and to stimulate research into these pain syndromes.