This document describes a method for the determination of the loss on ignition (wLOI) of fine, intermediate, composite and coarse soils, organic soils and anthropogenic materials (according to EN 16907-2) after ignition under air at 550°C. The loss of mass suffered by these materials at 550 °C is usually due to the release of volatile compounds, water (absorbed, crystalized or structural) and gases from decomposition of organic matter and inorganic substances such as sulfur, sulphides or hydroxides (e.g. H2O, CO2, SO2). A method is given in Annex B in order to estimate the organic matter content (COM) from the value of wLOI for clayed soils.