Background:The development of antibodies against coagulation factor VIII (fVIII) is a serious complication of hemophilia A. Results: Small angle x-ray scattering reveals a molecular envelope solution structure of two inhibitor antibodies bound to the C2 domain of fVIII. Conclusion: Multiple inhibitor antibodies can bind to the fVIII C2 domain simultaneously, and modeling suggests the localization of key epitopes. Significance: Understanding fVIII-inhibitor interactions is crucial for developing more effective hemophilia A therapies.