The objective of this research was to characterize the viscoelastic behavior of the fluids used in enhanced oil recovery by chemical flooding methods. By a better understanding of the rheological properties controlling porous media flow, more reliable and efficient design can be achieved and more economical oil recovery can be attained. Two polymers, a xanthan gum having a molecular weight near 2 x 10 6 daltons and a hydrolyzed polyacrylamide, were selected for application to a variety of rheological evaluations and porous media flow tests. The most conspicuous difference was that the hydrolyzed polyacrylamide showed pronounced dilatancy in porous media flow while the xanthan gum did not. Cross linking in situ was evaluated for the polyacrylamide.