This investigation constitutes an attempt towards(1) understanding issues and problems relating to the notions of one, many, part and whole in Parmenides and Plato; (2) extracting conditions for a successful account of multiplicity and parthood;(3) surveying Deleuzian conceptions and uses of these notions; (4) appraising the extent to which Deleuze’s metaphysics can answer some of these ancient problems concerning the status of multiplicity and the nature of mereological composition, that is, of the relations that pertain between parts and the wholes that they compose.