The present invention relates to a method of identifying an inhibitor of a mammalian (e.g., human) C—C chemokine receptor 3 (CCR3), comprising combining (a) a compound to be tested, (b) a host cell expressing a recombinant protein comprising a mammalian CCR3, and (c) a ligand of said receptor, under conditions suitable for binding of ligand to said receptor, and detecting or measuring the formation of a receptor-ligand complex. Inhibition of complex formation by the compound is indicative that the compound is an inhibitor.