The inadequate management of pain continues to be a significant problem for cancer patients. The purpose of this descriptive study was to compare the pain assessments of the nurses and cancer patients, and analize the factors affecting the pain assessments. The sample of study was consisted of nurses n=40 working in oncology clinics of a state hospital and a training hospital and eighty cancer patients hospitalized in these clinics. The Questionaire Form for Patients, Questionaire Form for Nurses and Visual Analogue Scale were used in the collection of the study data. It is found that oncology nurses mostly considered verbal expressions of patients and no one of them used pain scale, less assessed pain than the cancer patients. Nurses’ education level, training about pain and working duration in oncology clinic effected their pain assessment. Bachelor's degree, continuous education and certificate programmes about pain assessment could be beneficial for nurses to assessment pain of cancer patients