During the postharvest period, chilling injury cause important produce losses in peppers. The chilling injury of pepper is revealed especially low temperature during storage. So, this study is contucted to determine the effect of ultrasound (52 dB) and oxalic acid treatments on chilling injury (CI) and color maintain of Capia peppers at 4°C temperature. The peppers harvested at the mature-green stage divided into four group and the following treatments were done; 1. Control (C, dip to water at 25°C for 15 min), 2. Oxalic acid (OA, dip to the3 Mol oxalic acid solution at 25°C for 15 min), 3. Ultrasound (US, dip to water bath in a 52 dB and at 25°C for 15 min), 4. US+OA (dip to the3 Mol oxalic acid solution in a 52 dB water bath for 15 min). After treatments, the peppers were dried, placed in polystyrene foam dishes as three pepper per dish, and wrapped polyethylene stretch film. Then, the packaged peppers were stored in a cold room at 4±1°C temperature and 85-90% RH. The study was carried out in three replicates, and total soluble solids (TSS), color (L*, a*, b*), weight loss, electrolyte leakage, visual quality scores and CI scores were determined during storage (at the beginning, 14th days, 14th+72h, 28th days, 28th+72h). According to the results, CI scores of samples in three treatments (OA, US, US+OA) were lower compared to control group. But, OA treatment was supressed CI symptoms than the other treatments during all storage period. The color preservation of samples in OA, US, US+OA treatments were lower than control. In conclusion, it was concluded that,
