OBJECTIVES: Hemophilia A is a rare hereditary bleeding disorder with serious consequences. Replacement therapy is normally administered, either prophylactically or on demand. Economic aspects have been little researched. Therefore, we conducted a cost analysis using data from the Hemophilia Treatment Centre in London, Canada, where all patients are treated prophylactically. METHODS: We reviewed charts of all severe hemophilia patients (n=6) from time of diagnosis until the present, identifying resources consumed, then costing from the Ministry of Health perspective. Patients having complications, such as inhibitors, HIV, or hepatitis, were excluded. For each subject, we determined the costs of Factor VIII, hospitalization, port-A-catheter insertions and complications, treatments, homecare and physician/clinic visits, in Canadian 1997 dollars, discounted at 3%. RESULTS: Data were available from 1988 to 1999. The total average cost (range) was $51,994 ($2,171-$75,516)/patient/year. Factor VIII was the major cost driver [$48,772 ($802-$73,483)] comprising 94% (37%-97%) of all expenditures. Average hospitalization cost/patient was $1,190 ($0-$15,877), including surgery, drugs, nursing care and stay. In total, there were 11 hospitalizations [0.3 (0-1)/patient/year], which lasted 57 hospital days [1.6 (0-8)/patient/year]. Treatment cost per bleed was $613 ($0-$2875). Patients had 76 bleeds in total [2.2 (0-14)/patient/year]. Catheter costs were $428 ($0-$1975) and complications added $326 ($0-$727), clinic visits contributed $572 ($484-$723) and home care added $92 ($0-$371). Total costs increased linearly over time [yearly cost=$4,774.1 per year + $10,307 (r2=0.54)], as did Factor VIII cost [yearly cost=$5,263 per year+$3064 (r2=0.61)]. CONCLUSIONS: In this series of severe hemophilia patients, prophylactic treatment was found to be very expensive at more than $50,000 per patient. However, the results were sensitive to the clotting factor unit cost, which comprised 94% of the total average cost/patient/year. For all patients, a decrease in number of bleeds, hospitalizations and hospital days was observed over time, suggesting increasing quality of life.