This paper presents a layout optimization methodology for the topside deck of a floating liquefied natural gas facility (FLNG) using inherent safety principles. Natural gas is emerging as a clean energy, and a large amount of natural gas exists in the proven offshore area, thus making it an energy source with huge potential in today's and the future market. FLNG facilities tap natural gas from an offshore well by floating, compressing it into liquefied natural gas (LNG), and offloading it to LNG carriers after temporary storage. In addition, FLNG facilities enable long-distance as well as multilocation transportation. The FLNG facility requires compact design due to limited space and high construction costs and thus faces a more challenging situation where the design has to concurrently guarantee economic profits and a safe operational environment. Therefore, the layout of the topside deck, which includes production, storage, and other functions, plays a paramount role in designing an FLNG facility. This paper optimizes the layout of an FLNG topside deck by implementing inherent safety principles. The objective is to design a topside deck layout which achieves the largest extent of inherent safety with optimal costs. The details of the principles and their application for layout optimization are also provided.