While a decrease of wild felid population has led to disruption of conservation programme, recent studies have shown the importance of immune regulation for determining health outcomes and co-infection. Immunoglobulin G is important for detecting and evaluating responses to infectious diseases and vaccination. But, there is limited information on felid immunoglobulins and their role for functional immunity. This study aimed at isolating and characterizing lion’s immunoglobulin G. Lions’ sera (n = 68) were processed using the MagReSyn® magnetic beads and the final protein concentration was determined using the Xpose™ Trinean Spectrophotometer. The cross-reactivity of goat anti-cat immunoglobulin with sera of lions and other species was analysed using ELISA. High cross-reactivity was observed in lions ranging from 87.7 to 100%, and low reactivity with rhino (22.4%) followed by chicken (0.01%). The protein concentration from purified sera yielded 39.09 mg/ml. Molecular weight of lion IgG 150-160 kDa was detected with both chains at 54-56 kDa and 24-26 kDa on SDS PAGE. These results indicate a potential aid in developing serological tools to monitor exposure to micro-organisms of lions. / Agriculture and  Animal Health / M. Sc. (Agriculture)