Immobilization in the intensive care unit can lead to pressure injuries and plantar flexion contractures. This study was conducted to evaluate the effectiveness of heel protectors applied for the prevention of heel pressure injuries and plantar flexion contractures in intensive care units. This study was conducted as a randomized controlled trial in two adult intensive care units of a teaching and research hospital. The study sample consisted of 84 patients admitted to intensive care units between January 2022 and December 2022. Patients who had been in the intensive care unit for at least 5 days, scored 16 or less on the Braden Pressure Ulcer Risk Assessment Scale and scored 4 or more on the Ramsey Sedation Scale, were included in the study. Heel protector boots were applied to the heels of the patients in the intervention group, while standard positioning with a pillow and ROM exercises were continued in the control group. A sociodemographic data form, the Ramsey Sedation Scale and the Braden Pressure Ulcer Risk Assessment Scale were used to collect data. While pressure injuries were evaluated with the International NPUAP-EPUAP Pressure Ulcer Classification System, goniometric measurements were made to evaluate joint ROM. In the intervention group, heel pressure injuries did not develop during the study, whereas five patients in the control group developed heel pressure injuries. The risk of pressure injury development that was seen in the control group was 1.7 times higher compared with the risk for the intervention group (log 95% CI: 0.91-2.59). There were significant differences between the right foot (99%; F = 99.229; p = .000) and left foot (99%; F = 100.519; p = .000) in range of motion measurement values of the patients in the intervention group according to the measurement times. According to the results of the multiple comparison test (Bonferroni) performed to determine the range of motion measurement periods showing significant differences, it was observed that each measurement for both feet yielded lower results than the previous measurement (seven measurements from day 1 to day 13). The use of heel protector boots was found to be effective in preventing the development of heel pressure injuries and plantar flexion contractures in intensive care unit patients. This study provides evidence that intensive care nurses can use heel protector boots to prevent the development of heel pressure injuries and plantar flexion contractures.