Summary form only given. A load transient mitigation technique is proposed in this paper for stand-alone fuel cell-battery power systems. The technique can be used not only to improve the output power quality of the overall system, but also to mitigate or eliminate the electrical feedback stresses upon fuel cells caused by load transients. As a result, the durability of fuel cell can also be improved. System analysis and controller design procedure for the proposed technique are given in the paper. Simulation studies have been carried out for proton exchange membrane fuel cell (PEMFC) and solid oxide fuel cell (SOFC) based power systems. Simulation results show the effectiveness of the proposed technique in preventing load transients to affect fuel cell performance.