Introduction: The problems and the complications regarding hypothermia in the operating room are well known historically. The struggle of keeping the patient warm is still problematic. Hypothermia creates extensive complications and suffering for patients and is potentially lethal. Purpose: To explore the operating- and anesthesia nurses experiences in preventing hypothermia perioperative Method: A qualitative interview study using phenomenografic approach. The research group consisted of operating- and anesthesia nurses from a medium sized hospital in Sweden. Semi structured interviews were conducted. Results: The study revealed three concept categories. That knowledge leads to understanding which indicated that the knowledge of why hypothermia needs to be prevented raised awareness and compliance. Understanding the importance of communication and teamwork that highlighted the importance of communicating and strive towards the same goal. Working with conditions and obstacles that showed the importance of using available instrumentalities to prevent those obstacles that remains. Conclusion: This master thesis contributes to highlighting the importance of knowledge in the preventive work around hypothermia. Strengthened teamwork between operating nurses and anesthesia nurses creates a better condition in protecting patients against unwanted hypothermia and creating a safer surgical care.