Ligninolytic enzymes activities (laccases, peroxidases (total, MnP and MiP) and aryl-alcohol oxidase (AAO)) were measured during the cultivation of six commercial Pleurotus sp. strains on MMP media, on cereal grains (spawn) and on straw substrates (the three commonly utilized cultivation steps to obtain fruiting bodies) supplemented with several concentrations of autoclaved (OMW) or gamma-irradiated (iOMW) olive mill waste. Results indicated that all the strains were able to grow on MMP media and spawn containing up to 30% OMW and iOMW and on straw substrates mixed with 50% OMW. None of the strains showed AAO activity and there was not a single strain which showed the highest laccases and peroxidases activities, independently of the utilized substrate. Pleurotus mycelia adjusted their enzymatic mechanisms depending on their variety, type of substrate, concentration of OMW or iOMW added. OMW was a better supplement to use than iOMW because OMW induced higher exo-enzymes activities.