The purpose of this International Standard is to describe a method for assessing genotoxic effects (chromosome breakage or dysfunction of the mitotic spindle) of soils or soil materials on the secondary roots of a higher plant: Vicia faba (broad bean). This method allows the assessment of genotoxicity (toxicity for genetic material) of soils and soil materials like compost, sludge, waste, fertilizing matters, etc. Two ways of exposure can be considered: a direct exposure of plants to the soil (or soil material) which is relevant for the real genotoxic potential and an exposure of plants to the water extract of the soil (or soil material). This last way of exposure to a leachate or an eluate allows the detection of the mutagens which are not adsorbed to soils and which may be transferred to aquatic compartments. Moreover, this test may be used to evaluate genotoxic effects of chemical substances and to waters, effluents, etc.