Histopathological findings are important to the understanding of toxicity profiles of pesticides. The liver is often a target organ of chemicals. In the present study, histopathological findings in the liver cited in the pesticides risk assessment reports published by the Food Safety Commission of Japan were classified. The histopathological findings were obtained in repeated-dose 90-day oral toxicity studies of mice, rats and dogs and carcinogenicity studies of rodents. After the classification, a thesaurus was constructed based on the International Harmonization of Nomenclature and Diagnostic (INHAND) Criteria. We recommend the use of INHAND criteria in risk assessment reports to improve mutual understanding between applicants and risk assessors.