Abstract: Background and Objective: Particle size distribution (PSD) is the main predictor variable used in Pedotransfer functions (PTFs). Verification of PTF requires a specialized database. These databases contain PSD measured by sedimentation methods either using pipette or hydrometer method. Recently, laser diffraction method (LDM) is widely used for particle size distribution measurement. The aim of the research was to validate usage of laser diffraction method instead of pipette method for estimating soil saturated hydraulic conductivity, using PTFs. Materials and Methods: Soil saturated hydraulic conductivity (KS) was measured by constant head method technique and calculated by PTFs. The calculated PTFs were based on PSD measured by laser diffraction method (LDM) and by pipette method (PM) for estimating KS. Saturated hydraulic conductivity (KSPM) was calculated by pipette methods (PM), while KSLDM was calculated by LDM, using PTFs. Results: The results observed that lower clay fraction measured by LDM than that measured by the PM, while higher silt fraction measured by LDM than that measured by PM. In spite of, there is no agreement between the PSD obtained by LDM and PM. However, it didn't change soil type texture. The root mean square error (RMSE) of KSLDM (2.41×10–6 m sec–1) was relatively close to RMSE of KSPM (2.63×10–6 m sec–1). Conclusion: LDM technique can be successfully used for estimating soil hydraulic properties using PTFs, without any modification or recalculations for silty loam and silty clay loam soils under study.