A practical application of pressure transient analysis (PTA) and 4D seismic for monitoring movement of flood fronts and determination of hydrocarbon saturations in a waterflooded reservoir is presented. A novel workflow for quantitatively integrating 4D seismic data with PTA is described. At the injectors, pressure falloff tests were analyzed to reveal the progression of the flood fronts by using analytical radial composite models. Seismic interpretations of flood fronts were incorporated and refined in the numerical PTA model to examine flood front anisotropies. Sensitivity analysis with numerical PTA of the 4D interpreted flood fronts reduced uncertainties in their size, shape and location. Analytical and numerical PTA techniques were used to determine the range of pressure-saturation conditions in the reservoir at the time of the monitor seismic survey that could explain the lack of 4D signal around the producers. Unique multiphase effects were observed in producers -like the appearance of artificial "humps" in the derivative -which were explained by means of numerical models with gas saturation gradients. Results from the integrated 4D-PTA approach reduced uncertainties in the predicted pressure and saturations around the injectors and producers. The results from these techniques can be used to improve reservoir characterization and reduce uncertainties in remaining reserves. The integrative workflow can lead to upgrades in the reservoir-management strategies, increasing the realized economic value of both PTA and 4D technologies. Application of the integrated PTA-4D techniques allow for early field intervention and optimized placement of development wells.