The rheological characterization and modeling of maltenes blended with a commercial styrene-butadiene-styrene block copolymer (SBS) is presented in this study. Unmodified Maltenes (UM) were obtained from AC-20 Asphalt (PEMEX, Salamanca) by means of the standard n-heptane separation process. UM were mixed with different amounts of SBS Elastomer (E) (0.25, 0.50, 1.00, 1.50, 2.00, 40, 50, 60 and 80% wt.), to investigate the effect of polymer concentration on the rheological behavior of the blends; storage G’ and loss G’’ moduli were obtained from oscillatory linear viscoelastic tests. The rheological behavior of these mixtures was modeled by using the multimodal Maxwell model. In fact, the A-E system are simple thermorheologically material with a predominantly viscous behavior. Han, Cole-Cole and Van Gurp-Palmen diagrams were prepared from the rheological data, two different responses were observed: At low elastomer (SBS) contents, a dispersed system rheological response was observed and verified by microscopy studies with the polymer as the dispersed phase and the maltenes as the matrix while at high polymer content the response was that of a co-continuous system, no evidence of phase inversion was detected. Results showed a well-defined Newtonian plateau at low E concentration, however, at >2% wt. of E the mixtures exhibited an important change in thermomechanical properties.