In accordance with Article 6 of Regulation (EC) No 396/2005, the applicant Taminco BV submitted a request to the competent national authority in Austria to modify the existing maximum residue level (MRL) for the active substance chlormequat in oat grain. The data submitted in support of the request were found to be sufficient to derive an MRL proposal for oat. According to available livestock feeding studies, there is indication that for most of the animal matrices lower chlormequat MRLs would be sufficient to account for the current EU dietary burden. Adequate analytical methods for enforcement are available to control the residues of chlormequat and its salts (sum, expressed as chlormequat chloride) in the commodity under consideration and in animal matrices at the validated limit of quantification (LOQ) of 0.01 mg/kg. Based on the risk assessment results, EFSA concluded that the short‐term and long‐term intake of residues resulting from the use of chlormequat chloride according to the reported agricultural practice is unlikely to present a risk to consumer health.