The mycelial growth kinetics, cadmium biosorption capacity and main governing biosorption mechanism of Pleurotus ostreatus (oyster mushroom) have been determined in this study. The fungus mycelium exhibits a sigmoidal (S-shaped) growth curve in which the growth rates for the lag and exponential phases are 0.1 and 0.31 g/L·day, respectively. The grown fungus is subjected to elemental, infra-red and scanning electron microscopy-energy dispersive x-ray spectroscopy analyses, while biosorption data are fitted to established adsorption isotherm models, namely, Langmuir, Freundlich and Dubinin-Radushkevich. It is strongly suggested that the main governing mechanism involved is chemisorption due to good fitting of biosorption data to Langmuir and Dubinin-Radushkevich models with possibility of involvement of both ion exchange and complexation. Data presented in the study are very useful for design of future pilot- or industrial-scale biosorption water purification systems.