Peat deposits are the partly decomposed and fragmented remain of plants that have accumulated under water (excessively moistened) and fossilized, and consist of more than 50% organic substances. This type of subsoil foundation has high compressibility and low shear strength when subjected to imposed loads from civil engineering projects. It is essential to distinguish this problematic soil from better quality soils. Visual inspections including colour (dark brown to black) and odour (organic odor) tests can help to recognize peat. Field strength evaluation tests such as FVST and PLT can give good estimates of peat shear strength. Also laboratory tests such as moisture content, organic content and UCS and CBR may be used to evaluate peat physical and mechanical properties as well.