<p>The main purpose of this research is to evaluate the change in quality properties and bioactive compounds of chestnut <i>(Castanea sativa</i> Mill. cv. ‘Ünal’) treated with different doses (400 and 800 µmol L⁻¹) of methyl jasmonate (MeJA) during cold storage. The nuts were stored at 0 ± 0.5 °C and 90 ± 5% relative humidity for 80&#xa0;days. Compared with control nuts, the weight loss of high-dose (800 µmol L⁻¹) MeJA was lower in the last two measurement periods of cold storage. On the 20th day, the respiration rate was lower in both MeJA and only 800 µmol L⁻¹ MeJA in the other measurement periods. Firmness, L*, chroma, hue angle and ash values of all applications were similar. At the end of the storage, lower dry matter was obtained in the 800 µmol L⁻¹ MeJA application than control. However, in the 400 µmol L⁻¹ MeJA application, higher crude protein was measured compared to the control. At days&#xa0;40, 60, and&#xa0;80 of storage, the soluble solids content (SSC) of MeJA-treated fruit was lower than in the control. On day&#xa0;20, acidity was lower in MeJA-treated fruit than control. During storage, higher total phenolics and antioxidant activity (except for 40&#xa0;days in the ferric reducing antioxidant power [FRAP] assay) was measured from MeJA-treated fruit compared to the control. As a&#xa0;result, it has been revealed that MeJA can be used as a&#xa0;tool to delay the postharvest weight loss of chestnut (800 µmol L⁻¹ MeJA) and to maintain its antioxidant activity.</p>