The development of alloantibodies (inhibitors) against coagulation factor VIII (FVIII) is the most serious complication of FVIII replacement therapy in patients with haemophilia A (HA). We carried out a nationwide study focussing on patients with HA with inhibitors in China to evaluate the condition and management of this population. The study retrospectively analysed patient characteristics, clinical history, manifestation, treatment strategy as well as individual haemophilia care of 493 patients with inhibitors (466 with severe HA and 27 with non-severe HA) registered all over China. The median (interquartile range) age at diagnosis of FVIII inhibitors was 13 (5-28) years in patients with severe HA and 24 (10 center dot 5-39 center dot 5) years in patients with non-severe HA. Most patients (85%) had high-titre inhibitors. Prothrombin complex concentrate and recombinant activated coagulation factor VII were used respectively in 76 center dot 2% and 29 center dot 2% of patients for acute bleeding. Only 22 center dot 3% of patients underwent immune tolerance induction (ITI) treatment, of whom 64 center dot 9% achieved negative inhibitor titre. In patients who did not undergo ITI, the inhibitors turned negative in 17 center dot 7%, and patients with low peak inhibitor titre were more likely to acquire negative titre spontaneously (odds ratio 11 center dot 524, 95% confidence interval 5 center dot 222-25 center dot 432; P = 0 center dot 000). We recorded that 3 center dot 2% of the patients died from haemophilia-related life-threatening bleeding.