Background: Pain is the fifth vital signs and the most common indicator of sickness or damage caused by a simple sensory response mechanism. Pain has been identified as the most critical and poorly controlled symptom affected cardiac surgery patients’ total recovery. Purpose: The study purposed to assess knowledge, attitudes and practices of nurses regarding postoperative pain management among patients with open heart surgery at hospital in Al-Jouf, Saudi Arabia. Methods: The study was a descriptive cross sectional study design. A convenience sample of 121 nurses were recruited from governmental hospital in Al-Jouf and assessed in relation to knowledge, attitudes and practices towards pain management. Results: The study results revealed that the majority of nurses have moderate knowledge about pain management after cardiac surgery. In addition, nurses also showed to have neutral attitudes towards pain management and poor practice to manage pain. Conclusions: Pain management is ineffectively managed by nurses. Nurses need to adhere to best practices in pain management by increasing their theoretical and practical knowledge, so that there will be tangible positive change in pain management. Recommendations: The study results demonstrate the importance of delivering education intervention to enhance nurses' awareness regarding pain assessment and non-pharmacological pain management of patients after cardiac surgery.