Microwave technology is utilized in many fields, especially in measuring the dielectric properties. In this study, the dielectric properties of a complete Oil Palm Trunk (OPT) log are investigated for both healthy and unhealthy (has hollow inside) samples to be used for imaging purpose (to reconstruct an image of the hollow in an unhealthy sample). An open-ended coaxial probe technique is used for measurement. Both Dielectric loss and loss tangent follow the same trend through most of the frequency band. Although the current sample is bigger than recent similar works, the dielectric constant and dielectric loss are positively harmonized with its moisture content. Furthermore, the results are more realistic than recent related works since a complete sample with all its layers is used not only the core as presented in the literature. © 2019 Author(s).