Derived categories in algebra and topology by J.P. May Abstract An analogy between the derived category of modules over a commutative ring and the stable homotopy category of spectra is elaborated to a much closer analogy between the derived category of E infinity modules over an E infinity algebra and the derived category of E infinity module spectra over an E infinity ring spectrum. In both the algebraic and topological contexts, these new derived categories allow one to study ``modules up to homotopy'' over ``commutative algebras up to homotopy'' in much the same way that one studies ordinary modules in classical homological algebra. There are many applications in algebraic topology, algebraic K-theory, and algebraic geometry. This expository note explains the ideas and gives a brief summary of the relevant definitions in both contexts. This paper will appear in the proceedings of the Eleventh International Conference on Topology, Trieste, 1993.