Abstract: Different ratio of substrates combination between sawdust and cattails were used for Pleurotus ostreatus cultivation and 3-6 flushes were obtained from these substrates. A substrate combination between cattails+sawdust or cattails alone was not accelerated the mushroom growing processes. The mycelial completed colonization, primordium initiation and fruiting body formation were delay when compare to sawdust alone (control). Less yields were revealed from all cattails cultivation substrates (112.10-289.63 g) and these yields were significantly different to those found from control (536.85 g) at a confidence level of 95%. Moreover, the percent biological efficiency (%BE) values obtained from all cattails cultivation substrates were nearly two times less than those found in control (95.02%). Even the cattails are undesirable weeds and provides an economically acceptable substrates but less yields, low %BE and more time consuming were obtained in mushroom growing processes therefore the substrate combination of sawdust+cattails or cattails alone have shown low potential for use as a raw material for P. ostreatus cultivation.