The invention provides a method for separating a Factor VIII (FVIII) protein from a first composition comprising the FVIII protein, which contains at least the light chain of FVIII, and a von-Willebrand-Factor (vWF) protein which comprises at least the FVIII binding domain of vWF, wherein the FVIII protein can form a complex with the vWF protein, the method comprising the steps: contacting the first composition with an affinity resin comprising a ligand and a matrix, wherein the ligand has an affinity to the light chain of FVIII, and separating the affinity resin from the mixture to obtain a modified first composition and a second composition, wherein the second composition contains the affinity resin, and a complex of the FVIII protein and the vWF protein.