The metal ion response profile and thermal stability of extracellular laccase from Pleurotus ostreatus strain EM-1, which is widely cultivated in Ghana, were investigated to provide information essential for the establishment of laccase-based applications in the country. P. ostreatus (Jacq. ex. fr) Kummer strain EM-1 was cultivated on a mixture of Triplochiton scleroxylon (wawa) sawdust, rice bran and lime.