The present disclosure relates to polypeptides (also referred to herein asCXCR4 binding molecules or polypeptides)that are directed against the G-coupled protein receptor CXCR4, also known asFusin or CD184. The invention also relates tonucleic acids encoding such polypeptides； to methods for preparing suchpolypeptide； to compositions, and in particular to pharmaceuticalcompositions that comprise such polypeptides and to uses of such polypeptidesfor therapeutic or diagnostic purposes.
