Pressure ulcers are complications among patient with chronic illness in most settings, especially among the hospitalized elderly and patients with spinal cord injuries. Impaired skin microcirculation combined with loading pressure, friction and shear force are crucial risk factors for development of pressure ulcers. This article aims to a review available research that has been conducted on skin microcirculation, as defined by skin blood flow and skin temperature, in hospitalized elderly and patients with spinal cord injuries. A review of 18 studies revealed that, healthy or ill elderly, as well as patients with spinal cord injuries, were all experience impaired ski microcirculation. A combination of loading pressure and impaired skin microcirculation were found to be crucial pressure ulcer risk factors for the hospitalized elderly and patients with spinal cord injuries. Implication of effective strategies to promote skin blood flow and decrease skin temperature for nursing practice and future research are suggested.