Polyethylene terephthalate (PET) is one of the packaging materials that is widely used for packaging of soft drinks. PET may contain acetaldehyde which is a thermal degradation product, and hence acetaldehyde may migrate into the product in the package. In this study, the migration of acetaldehyde from PET bottles into soft drinks containing carbonic acid was determined by gas chromatography without headspace instrument. Carbonated beverage samples obtained from four different firms following the filling process were stored at 5, 20 and 40 degrees C for 6 months and analysed periodically at 0 day, 2, 4 and 6 months. As a result, it was seen that the acetaldehyde concentrations of all samples were quite different from each other and also related to the storage temperature, and an increase in storage time raised acetaldehyde concentrations in beverages. Especially, storages at 40 degrees C had very serious effect on acetaldehyde concentrations in the beverages.