Korean fermented red pepper paste was packaged under a modified atmosphere (MA) of 30% CO2/70% N-2 and 100% CO2. A plain air package was also prepared as a control for comparison. The MA conditions were applied with a high gas barrier film and subsequently with a gas permeable film. Throughout the storage period at 13 degreesC, package volume, headspace gas composition, microbial flora, surface colour, pH and acidity were measured. An MA of 100% CO2 suppressed the growth of aerobic bacteria and yeasts, and reduced the CO2 production from the paste without any adverse effect on product quality, and thus alleviated the volume expansion of flexible packages stored at 13 degreesC. However, the reduced volume expansion for the package of high-barrier film was not sufficient in prolonged storage. An MA package of 100% CO2 using plastic film of appropriate gas permeability could be stored at 13 degreesC for 150 days without volume expansion or any adverse quality changes, and was also tolerant to temperature abuse conditions at 25 degreesC.