The effective axial thermal conductivity is an essential parameter for an accurate description of heat transport in packed bed reactors. This work presents an experimental setup to determine this parameter from high-resolution axial temperature measurements. The optimized measuring technique improved the procedure, solving issues reported by other studies, such as misalignment and disturbance of multiple thermocouples. Different materials were investigated: steel spheres, alumina spheres, and steatite hollow cylinders. Furthermore, correlations for these materials were determined.