With advancing technology, printed circuit board (PCB), one of the most important components of ewaste, has become a source of pollution due to an ineffective waste management system. This problem can be solved by converting PCB waste into a valuable product which will emerge to maximize the renewable energy supplies. In this aspect, co-pyrolysis is advantageous in both simple and successful in producing high-quality pyrolysis oil. In this paper, cotton stalk (CS) as biomass was used and pyrolysis of PCB, CS, and a mixture of both in 1:1 have been carried out. CS has a good combustibility at 500°C which was chosen for the pyrolysis reaction in a fixed bed reactor for slow pyrolysis. The pyrolytic oil was analysed by GC–MS and FTIR. The results indicate that there is an increase in oil yield from 19.6% to 27.5% by weight and phenol and phenolic compounds in oil of co-pyrolysis from 60.94% to 76.82% compared to literature available. There is an increase in bromine solidification in char by 25% with a mixture of CS and PCB compared to CS and PCB individually which is much higher than literature data. To the best of the authors’ knowledge, co-pyrolysis of PCB:CS has been attempted first time and debromination of oil was found excellent in the present work.