Soil hydraulic parameters have high spatial variability. A large number of measurements are needed to characterize these parameters in a field. Therefore there is a need to develop quicker and cheaper methods to determine soil hydraulic parameters. The objective of this study was to examine the uniqueness of the Kfs (field saturated hydraulic conductivity) and α (inverse macroscopic capillary length scale) parameters obtained through inverting the falling head infiltration model. Five simulated scenarios were imposed on the cumulative infiltration data <L(t)> during the inverse procedure. The uniqueness of the Kfs and α estimates under each scenario was studied. In situ infiltration data were used to verify the scenario that provided unique parameter estimates. It appears that the falling head infiltration model can be used to simultaneously estimate the Kfs and α parameters when estimates (or published values) of the α parameter for the site are available.