The in vivo alkaline Comet assay detects primary DNA damage in various organs and tissues of exposed animals and can be used to assess the genotoxicity of a great variety of chemical compounds, which include food additives, flavourings, food contact materials, foodborne by-products, pesticides, contaminants, etc. Among the various versions of the assay, the alkaline method (pH of DNA unwinding and electrophoresis buffer > 13) identifies the broadest spectrum of DNA damage and is, therefore, recommended for regulatory purposes. It can detect double- and single-strand breaks, alkali-labile lesions that are expressed as single-strand breaks and single-strand breaks arising as DNA repair intermediates. No OECD Test Guideline yet exists for the Comet assay but internationally agreed protocols are available for performing this test. Since establishing of an OECD Test Guideline for this assay will require some further time, there is a need for an agreed approach on the minimum requirements on conduction and reporting of the in vivo Comet assay, which should be fulfilled for the purposes of EFSA during this transition period.