Helix aspersa are a useful tool to evaluate soil pollution, using chemical measurements associated with biological monitoring to assess the effect of contamination. Bioindicator organisms can reveal the biological impact of xenobiotic pollutants on the environment and be used for testing in the laboratory under controlled conditions. Among terrestrial invertebrates, the snail H. aspersa can accumulate different classes of chemicals and therefore is a relevant species for monitoring contaminated soils. This chapter presents the field and laboratory methods for using the land snail H. aspersa to characterize genotoxic effects of soil pollutants.