Aims: This research was done to assess the dechlorination and destruction of polychlorinated biphenyls (PCBs) in real-waste transformer oil via microwave (MW) radiation. Materials and Methods: The influence of MW power, reaction time, polyethylene glycol, zero-valent iron powder, sodium hydroxide (NaOH), and water (H 2 O) were investigated on the dechlorination and destruction efficiency of PCBs in real-waste transformer oil under MW radiation. Results: The findings show that polyethylene glycol and NaOH have great influence on destruction of PCBs. However, iron (Fe) did not have any influence, and H 2 O decreased the destruction efficiency of PCBs. Moreover, experimental data showed that with optimum amount of variables [ie, polyethylene glycol (PEG) = 5.4 g, NaOH = 1.13g, Fe = 0.6g, H 2 O = 0.8 mL, and MW power of 800 W], more than 99.9% of PCBs were destructed at reaction time of 6 min. Furthermore, destruction of PCBs in the absence of water increased up to 100% after 6 min. Conclusion: Accordingly, results showed that MW radiation and reactants (PEG and NaOH) were very important factors for the destruction of PCBs from real-waste transformer oil.