This paper demonstrates that microwave enhanced thermal decontamination of oil contaminated waste is a potentially important and highly efficiency approach to achieving the required environmental discharge limit. Numerical simulation of microwave thermal decontamination of oil contaminated wastes within an applicator known to support high electric field strengths was used to assess the influence of electric field and power loss density distributions on oil removal from the waste materials. It was found during this study that the water content plays the most important role in oil removal. As the microwave receptors within the material matrix, water molecules absorbed the bulk of the applied microwave energy. This energy was subsequently transferred to the oil in the form of heat, and was shown to cause thermal desorption. The boiling point of oil can also be reduced when it is mixed with water, since free water is beneficial to uniform heating, whilst bound water has a significant effect on the latter stages of oil removal. The experimental and simulation results suggest that the lowest residual oil levels were achieved when the sample material had a high dielectric loss factor and was placed in the position of maximum electric field strength. The cost of using a microwave technique for the remediation of oily waste can be up to 20 times lower than conventional heating.