Title:Algebras and modules in monoidal model categories Authors: Stefan Schwede, Brooke E. Shipley Email: schwede@math.mit.edu Email2: bshipley@math.uchicago.edu We construct model category structures for monoids and modules in symmetric monoidal model categories which satisfy an extra axiom, the monoidal axiom. This paper was inspired in particular to deal with two of the new symmetric monoidal categories of spectra, symmetric spectra and $\Gamma$-spaces. This paper is available at the homotopy theory archive at http://hopf.math.purdue.edu or via anonymous ftp at hopf.math.purdue.edu. It will also be available through math.AT at xxx.lanl.gov.