Sterculia urens is a moderate size deciduous tree. The study focuses on role of antioxidant enzymes during different stages of organogenesis and ex vitro acclimatization of regenerated plants. Enzymatic antioxidants like superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and polyphenol oxidase (PPO), total proteins and phenols were studied. The protein profile was studied by using SDS-PAGE and Iso-enzymes for CAT and POD were studied using native PAGE. Six POD and two CAT Isoenzyme forms were observed. The increasing concentration of total proteins and elevated levels of antioxidant enzymes were observed in regenerating callus at different stages with shoot initials than non-regenerating callus. The increased levels of proteins and peroxidase were also observed during acclimatization of in vitro regenerated plants.