Lipoxygenase, peroxidase and catalase activities were determined in tissues and brines of refrigerated dill pickling cucumbers in response to pickling process, storage and H₂O₂. Lipoxygenase was almost inactivated within 1 day exposure to dill pickling brine, and then gradually declined during storage. In contrast, peroxidase activity in cucumber tissue decreased steadily for 4 days after exposure to dill pickling brine. Catalase was present in fresh cucumber tissues, but only slight activity was observed after submerging cucumbers in pickling brine. Lipoxygenase, peroxidase and catalase activities were rapidly inactivated in cucumbers exposed to brine containing H₂O₂.