The purpose of this study is to examine the current composition of the fauna and flora of the mangrove ecosystem in Ranong, Thailand. Six (6) different sites located at three (3) districts were selected on the basis of the diversity of mangrove species. The Point Centered Quarter Method (PCQM) and direct observation were employed for floristic and animal inventory purposes respectively. With reference to the aquatic fauna structure, results indicated that there were twenty-seven (27) species present in the aforementioned areas. Scylla olivacea and Sardinella sp. were the most dominant species. On the other hand, the floristic composition totaled nineteen (19) identified species. Results point to the prevalence of Xylocarpus granatum, Bruguiera parviflora, Rhizophora apiculata and R. mucronata species. The dominance of these species in Ranong reveal several implications that describe the state of the ecosystem itself and ultimately, how it affects the human society of Ranong.