OBJECTIVES: GBS is a neuromuscular disease affecting 180 to 720 Canadians each year. Patients with GBS may be paralyzed for months, and up to 15% of affected patients are left with a long-term disability. Until relatively recently, standard therapy for GBS was a 5-day course of PE. As an alternative to PE, more recent randomized trials demonstrate that intravenous IVIG is equally effective to PE, but has fewer side effects and is easier to administer. Since clinicians have two options for the treatment of GBS, a cost utility analysis was conducted to determine which of these two treatments is the most cost effective. METHODS: A decision model was developed to simulate treatment response and disease recurrence over a 12-month time horizon. Clinical data were obtained from a meta analysis of randomized trials. Six experienced nurses were interviewed to obtain Health care resource utilization data. Utility values were obtained through interviews with 12 GBS health care providers using the Time Trade-Off technique. RESULTS: Based on the resource use data collected, the mean direct cost of a 5-day treatment of IVIG and PE was $9785 (95% CI: $9637-$9933) and $7508 ($6577-$8439) respectively. Using cost and utility estimates from IVIG and PE, the cost per quality adjusted life year (QALY) gained with IVIG was $35,700. In addition all of the health care providers interviewed preferred the use of IVIG instead of PE for their patients. CONCLUSIONS: For the treatment of GBS, IVIG has a more favorable side effect profile and is easier to administer than PE. These product attributes result in an incremental cost per QALY gained that is considered economically acceptable by current standards.