L-ornithine (L-Orn), is an intermediate metabolite in the urea cycle that plays an important role in the human beings and is used for the treatment of the liver diseases etc. Based on these versatile advantages, L-Orn is widely applied in the health care and pharmaceutical industries. In this study, l-arginase from Idiomarina sediminium was immobilized onto chitosan-hydroxyapatite. Effects of immobilization parameters including medium temperature and pH, enzyme concentration and coupling time was evaluated to obtain the best reaction conditions. The optimal immobilization pH was determined as pH 7.5 with the highest enzyme activity of 101.24 U chitosan-HAP beads and highest immobilization efficiency of 81.4%. Furthermore, the immobilized protein amount showed an increase with increasing enzyme concentration as expected. Characterization of immobilized enzyme was evaluated using l-arginine as a substrate. Immobilized enzyme exhibited better thermostability and higher stability at lower and higher pH values. Immobilization also resulted in a shift of 0.5 units in pH optimum for maximum enzyme activity. In contrast to optimum pH value, after immobilization no shift occurred in optimum temperature. Furthermore enzyme retained 81.8% of its initial activity during consecutive eight cycles. The results suggests that chitosan-HAP immobilized l-arginase can be employed on the large scale for industrial production of l-ornithine