Complexation (or the strong association) of oppositely charged polyelectrolytes is the basis for the layer-by-layer technique which has been widely shown to create thin films and coatings with a range of properties. The composition of these thin films has been shown to be directly linked to the solution phase behavior of the complex. Surprisingly enough, the solution association of polyelectrolyte complexes is less than well documented in the literature. Here we present results on the phase behavior of linear poly(ethylene imine) and poly(acrylic acid) complexes, including the influence of kinetic factors such as sitrring and order of mixing. The polyelectrolytes were characterized by GPC and the complexes were analyzed by Zeta potential measurements, light scattering, FTIR.