PURPOSE: In this study an examination was done of the effects of the American Society of PeriAnesthesia Nurses (ASPAN) Evidence-Based Clinical Practice Guidelines on body temperature, shivering, thermal discomfort, and time to achieve normothermia in patients undergoing total knee replacement arthroplasty (TKRA) under spinal anesthesia. METHODS: This study was an experimental study with a randomized controlled trial design. Participants (n=60) were patients who underwent TKRA between December 2011 and March 2012. Experimental group (n=30) received active and passive warming measures as described in the ASPAN's guidelines. Control group (n=30) received traditional care. Body temperature, shivering, thermal discomfort, time to achieve normothermia were measured in both groups at 30 minute intervals. RESULTS: Experimental group had slightly higher body temperature compared to control group (p=.002). Thermal discomfort was higher in the experimental group before surgery but higher in the control group after surgery (p=.034). It decreased after surgery (p=.041) in both groups. Time to achieve normothermia was shorter in the experimental group (p=.010). CONCLUSION: ASPAN's guidelines provide guidance on measuring patient body temperature at regular intervals and on individualized and differentiated hypothermia management which can be very useful in nursing care, particularly in protecting patient safety and improving quality of nursing.