The Haemophilia Utilization Group Study (HUGS) was created 10 years ago to examine the annual utilization and cost of haemophilia-related healthcare services. Retrospective chart reviews for 336 patients with haemophilia A receiving treatment in one of five comprehensive haemophilia treatment centres (HTCs) during 1995 were completed through interview of the provider. This method provided adequate collection of data from patient charts without the abstractor having direct access to patient health information. Utilization data were used to impute the costs of different components of care (e.g. physician visits, factor VIII concentrate, emergency room, hospitalization). The total annual cost of care was 139,102 dollars (SD $304,033). Factor VIII concentrate costs comprised the largest proportion of these costs; mean factor VIII concentrate use was 128,517 units per patient per year. Unbilled physician utilization accounted for 7.8% of the mean total physician costs per annum, while mean allied healthcare costs accounted for 33.5% of the total annual allied healthcare costs per patient. In the ordinary least-squares regression model, higher costs were associated with severe factor VIII deficiency, arthropathy, more comorbid conditions, an inhibitor to factor VIII concentrate, infusing through a port and prophylaxis. Although factor VIII concentrate is the most costly component, the treatment of haemophilia uses many healthcare resources. HUGS has demonstrated that patient clinical characteristics and physician practices predominantly drive the costs of haemophilia care. Specifically, patients with more severe arthropathy had greater healthcare costs. As future funding decisions are made, it is important to provide for all components of care.