The high cost of treating patients with inhibitors in an environment of restricted budgets warrants consideration of cost-effectiveness. We determined the clinical response, effect on quality of life and the cost-effectiveness of treatment with rFVIIa in six boys with long-standing inhibitors to factors VIII or IX, compared with other treatment regimes previously used in these patients. The study used a longitudinal before-and-after design and was conducted in three phases. Phase 1 was 6 months preceding the introduction of rFVIIa, during which patients received on-demand 'usual care' with other treatment regimes; phase 2 was 6 months treatment on rFVIIa assessed retrospectively; and phase 3 was 6 months on rfVIIa treatment assessed prospectively. Treatment with rFVIIa was reserved for intrarticular, compartment, psoas, mucosal and suspected intracranial bleeding. Treatment outcomes were obtained by interview using structured questionnaires, the quality-of-life instruments CHQ CF-80 and CHQ PF-50, patient self-reporting diary, interrogation of hospital records, and the EuroQoL EQ-5D for utility valuations. Our results confirm that rFVIIa is clinically effective and resulted in 63-92% reductions in the number of re-treatments, duration of painful episodes, delay to initiation of treatment, days requiring wheelchair or crutches, emergency room visits and lost carer time compared with the patients' other therapies. Quality-of-life improvements were observed in several important areas as perceived by both patients and their families, at an incremental cost per QALY of A$51 533.