Purpose: To examine knowledge and attitudes of nurses on post-operative pain, and to find the factors that hinder pain management by the nurses. Method: Data was collected using a questionnaire from all the nurses working in the surgical units and intensive care units in a hospital in Seoul between March 12 and 22, 2007. Data was analyzed with descriptive statistics, t-test, χ² test, and Pearson Coefficient Correlation. Result: The average knowledge score on pain was 9.33±1.55, and that for analgesics was 6.89±2.00. There was a significant difference in knowledge of analgesics in terms of career (p=0.012), present work place (p=0.024) and education (p=0.042). The knowledge on pain etiology was significantly different in career. Around 61.1% of respondents answered that they would administer analgesics immediately if patients complaint pain, and 94.1% re-administer analgesics if the VAS score is over 5. 69.3% thought that their knowledge was adequate for pain management. The attitudes of pain management were significantly different in career, Conclusion: We found that a further improvement on nurses’ knowledge on pain management and analgesics is necessary. This study also suggests a need for professional education for nurses on post-operative pain management.