ABSTRACTCoastal wetland loss in Louisiana, now considered to amount to more than 100 km2/year, is receiving ever increasing amounts of attention. This loss is the result of a variety of complex interactions among a number of physical, chemical, biological, and cultural processes. Important geologic phenomena include sea-level change, subsidence, compaction, and change in location of deltaic depocenters. Of the many catastrophic events that cause erosion, the hurricane with its high energy is the most important in Louisiana. Biological factors include rates of marsh growth (especially in relation to subsidence, compaction, and saltwater/freshwater proportion) and the degradation caused by marsh fauna.During the last few decades, the human factor in wetland loss has increased drastically. The placement of dams and levees across and along the tributaries and distributaries of the Mississippi River have reduced both the amount and texture of sediment reaching the coast. In addition, canal and highway construction in the wetlands has altered drainage patterns and fluid withdrawal is causing subsidence.To date, few of the processes responsible for land loss in south Louisiana have been quantified and the data sets that do exist are often in conflict with each other and reflect multiple interactions. However, the attention now being given wetland loss will hopefully provide more definitive answers in the near future.