The adsorption of moxifloxacin (MOX) by the spent coffee grounds (SCGs) was investigated. The effect of solution pH and the amount of SCGs were also studied. The optimum solution pH and amount of SCGs were 6 and 40 mg, respectively. The adsorption isotherms were well described by the Henry model. This suggested that the strong interaction of MOX with the SCGs. Therefore, SCGs, as a green, environmental-friendly adsorbent, can be applied to the adsorption of contaminants in environment.