Phytoremediation is the use of green plants and their associated microbiota, soil amendments, and agronomic techniques to remove, contain, or render harmless environmental contaminants. It is an emerging technology which offers a potentially cost-effective and environmentally sound alternative to the environmentally destructive physical methods which are currently practised for the cleanup of contaminated groundwater, terrestrial soil, sediments, and sludge. Mangrove wetlands are an important buffer for adjacent marine ecosystems. They are vital for healthy coastal ecosystems, which not only offer a nursery ground for a number of commercially or ecologically important aquatic organisms, but also provide prime nesting and migratory sites for birds and wildlife. This book summarises the recent progress in the research on the feasibility and potential of phytoremediation using constructed mangrove wetlands for wastewater and contaminated sediments.