Abstract In accordance with Article 16 of Regulation (EC) No 396/2005, the United Kingdom, hereafter referred to as the evaluating Member State (EMS), received an application from the company BASF SE to set a temporary maximum residue level (MRL) for the active substance mepiquat in cultivated fungi, based on monitoring data. This application was notified to the European Commission and the European Food Safety Authority (EFSA) and was subsequently evaluated by the EMS in accordance with Article 8 of the Regulation. After completion, the evaluation report was submitted to the European Commission and to EFSA. Mepiquat residues in cultivated mushrooms do not result from the use of the active substance on mushrooms, but from the uptake from the growth substrate composed of straw from cereals that have been previously treated with mepiquat. The monitoring dataset submitted by the United Kingdom was completed by additional data from national control programmes. Based on a total of 545 samples and on the Food and Agriculture Organization of the United Nations (FAO) approaches recommended for the setting of MRLs in spices and for the setting of extraneous MRLs (EMRL), EFSA derived three optional MRL proposals of 0.05, 0.07 and 0.09 mg/kg. It is proposed to risk managers to decide which value is the more appropriate to cover the presence of mepiquat residue in cultivated fungi. EFSA concludes that the highest MRL proposal for mepiquat will not result in a consumer exposure exceeding the toxicological reference values and therefore is unlikely to pose a concern for public health.