Katmon fruit has great economic potential, but little is known about its postharvest behavior. This study characterized the katmon fruit after harvest so that appropriate handling may be recommended to extend its shelf life during storage or market display. Physicochemical characteristics, particularly firmness, pH, total soluble solids (TSS), titratable acids (TA), and TSS:TA ratio were evaluated during storage under room condition (22ºC) and at low temperature (15ºC). These characteristics were almost constant under 22ºC or at 15ºC for two weeks, with pH at 2.8, TSS at about 3.40Brix, TA at 1.1% – 1.5%, and TSS:TA ratio at 3.10 – 2.04. Only moisture loss significantly increased, reaching 29% after the first week, which reduced the fruit’s shelf life and quality. Fruit in small quantities (1.5 kg) favorably responded to modified atmosphere packaging (MAP) using sealed polyethylene bags (PEB, 0.02 mm). About 15% O₂ and 0.45% CO₂ were maintained in PEB, which extended the fruit’s fresh quality up to two weeks under 22ºC. MAP was also able to maintain the firmness of intact fruits for two weeks when stored at 22ºC. In contrast, control fruits reached their limit of marketability after one week. Those without peel may also be kept for about two weeks when packed in PEB (300 g per pack), especially if stored at 15ºC.