Extended human life expectancy and expected shortages of health care workers promote the development of service robots. However, despite their advanced functionalities (e.g. serving as not only social companions for those under care but remote monitoring stations to assist caregivers), safety, reliability and lower life cycle costs remain as major issues that hinder service robots in being more widely commercially acceptable to the market and need to be addressed at both design and operation stages. Recent advances in prognostics and health management (PHM) technique enable the reliability of a system to be evaluated in its actual life-cycle operating environment and impending system failures to be predicted in advance. Capitalizing on the PHM technology in the operating system of service robots can mitigate dysfunctional risks, enhance reliability and reduce life cycle costs. This paper proposes the integration of the mobile robotics with the PHM technology to tackle reliability, safety, and life cycle cost issues of health care service robots. As the pioneer work in this new multidisciplinary area, this paper paves the way for PHM based health care robotics through: (1) introducing the current status of health care robotics industry, (2) addressing safety, reliability and life cycle cost issues of health care robotics, (3) presenting the PHM technique and potential life cycle benefits, and (4) summarizing the need for PHM in unmanned systems for commercial health care and home care for the elderly. We conclude that the embedded PHM technique, as exemplified by its successes in military and aerospace applications, can be implemented in service robots used in hospitals, invalid care or elder care environments.