OBJECTIVES: Kiovig is a new, ready-to-use 10% liquid immunoglobulin preparation that is medically indicated for the treatment of primary immunodeficiency. This study aims to conduct an economic evaluation which compares the intravenous immunoglobulin (IVIg) preparations Kiovig, Multigam, and Sandoglobulin from the Belgian societal perspective. METHODS: Given that three prospective studies have observed no difference in outcomes, a cost-minimisation analysis considered the differences in costs that can arise from these immunoglobulin products. A decision-analytic model simulated immunoglobulin treatment over a one-year time horizon. Cost items included immunoglobulin costs, pharmacy administration and nursing costs, mini-forfait paid for hospital infusion, costs of adverse events, and lost productivity. Cost data were identified from published sources and Belgian hospital administrators. A probabilistic sensitivity analysis explored the impact of parameter uncertainty. The price year was 2009. RESULTS: Costs per infusion cycle in adult primary immunodeficiency patients were €1.046 (95% confidence interval: €1.006 – 1.093) with Kiovig; €1.102 (€1.064 – 1.147) with Multigam; and €1.147 (€1.108 – 1.193) with Sandoglobulin.  The average cost savings per infusion with Kiovig as compared to Multigam and Sandoglobulin amounted to €56 and €101 per infusion. CONCLUSIONS: Treatment costs with Kiovig were shown to be lower as compared to other IVIgs in Belgium.  Reduced costs per infusion were attributed to lower costs associated with treating adverse events and the opportunity cost of nursing time and time off work for working adults.