Abstract. We aim to provide a more efficient way of processing multiplicative structure in the passage from permutative categories to spectra. In particular, we develop a multiplicative endomorphism operad for any permutative category, and show that under our passage to spectra, this endomorphism operad maps to the endomorphism operad of the associated spectrum. Together with the result that a permutative category supports bipermutative structure if and only if there is a map from a canonical E∞ operad into the multiplicative endomorphism operad, this gives a relatively simple proof that every bipermutative category gives rise to an E∞ ring spectrum. The other major result of our work so far is the development of a symmetric monoidal product on a certain category of permutative categories which captures all the homotopy information inherent in the category of all permutative categories.