Objective: This study was conducted on patients undergoing total hip replacements in order to examine the effect of the use of a gel foam mattress during surgery on preventing the development of pressure ulcers. Material and Method: A quasi-experimental design, with a pretest-posttest control group, was used for this study, which was carried out in the Orthopedics and Traumatology Clinic of the Adnan Menderes University Research and Treatment Hospital between July 2015 with 80 patients who were to undergo total hip replacement surgery (40 in the experimental group and 40 in the control group who were to undergo total hip replacement surgery and April 2016. Results: According to the research results, 30% of the patients in the experimental group and 60% of the patients in the experimental group developed pressure ulcers in the recovery unit (p=0.013). It was further observed, according to the results of Braden Pressure Ulcer Risk Assessment Scale (BPURAS), that the type of pressure ulcers in the patients who developed them was stage 1 and located in the gluteal region. Conclusion: Our results have been shown that the development of pressure ulcers in patients from both the experimental group and the control group in the recovery unit was related to age, operating time (min), anesthesia type, while height, weight, gender, diagnosis, temperature of operating theater. However, movement restrictions before surgery have not an impact on the development of pressure ulcers.