Lipid oxidation may occur during processing and influence subsequent oxidation during storage. Early oxidation during processing is in most cases very difficult to detect or measure with the methods commonly used for lipid oxidation. Still, this limited oxidation is of significant importance to the further oxidation and flavor stability during storage. This is illustrated by examples from experiments performed during manufacturing of potato granules and sausages, processing of cereals, and baking of cookies. The influence of processing on factors that affect lipid oxidation, e.g. prooxidants, antioxidants, oxygen content, and the protection against such oxidation are discussed.