In accordance with Article 43 of Regulation (EC) No 396/2005, the European Commission requested EFSA to prepare a reasoned opinion on the toxicological properties and the existing maximum residue levels (MRLs) set for propoxur. EFSA was requested to assess the toxicological properties of propoxur and derive toxicological reference values, based on the toxicological assessment performed by Health Canada. EFSA was also requested to review the information provided by Member States and the UK on the metabolism of propoxur in plants and animals and on the current MRLs, as well as the limit of quantification (LOQ) that can be achieved with analytical methods used in MRL enforcement. Based on the information available to EFSA, toxicological reference values could not be derived for propoxur. No evidence was provided by Member States and UK that the existing EU MRLs need to be maintained as import tolerances. Information to support the current MRLs or alternative MRLs have not been provided by Member States and the UK. Codex MRLs are not in place. EFSA therefore recommended lowering of all existing EU MRLs for propoxur to the LOQ. According to the EU Reference Laboratories, sufficiently validated analytical methods are available to analyse for propoxur residues in all plant and animal commodities. Lacking toxicological reference values derived at EU level, a conclusion cannot be derived whether the setting of MRLs at the LOQs is sufficiently protective for the European consumers.