The purpose of this study was to identify nurses' perceptions of knowledge and difficulties in cancer pain management. Data were collected from nurses (N=381) who provided care to cancer patients at hospitals in city A. The findings of this study were as follows: (1) Nurses who worked in non palliative care units had lesserknowledge about cancer pain management than nurses who worked in palliative care units; (2) Nurses who worked in non palliative care units, and had less than five years experience as a nurse, had lesser knowledge about cancer pain management than nurses who had more than five years experience as a nurse ; (3) Nurses who worked in non palliative care units, about 60%, never were educated in cancer pain management, hence, these nurses had less knowledge about the characteristics of cancer pain and the use of analgesics; and (4) Of the total sample, about 98% of nurses reported some difficulties in cancer pain management, and these nurses had difficulties in caring for patients who could not express their pain, or those who had complicated pain. The conclusion of the study is that nurses who worked in non palliative care units, especially those nurses with less than five years experience, and who were never educated about cancer pain management, demonstrated the need to improve their knowledge of cancer pain management.