In this study, the biosorption of copper(II) ions to the green alga Cladophora sp. was investigated in a packed bed column reactor as a function of flow rate and inlet copper(II) concentration. These two parameters affected the external mass transfer and adsorption rates directly. Mass transfer coefficients were determined from the Wakao Equation evaluating the breakthrough curves obtained at different flow rates. It was concluded that at a flow rate of 1.12 ml min(-1), mass transfer resistance was overcome and the mass transfer coefficient was determined as 6.7 x 10(-2) cm(2) min(-1). At this flow rate, the effect of inlet metal ion concentration on the adsorption rate was investigated and using the proposed model, the adsorption rate constant was predicted to be 5.53 x 10(-4) litre g(-1) min(-1). The adsorption rate step rather than mass transfer rate step limits the adsorption rate.