This paper discusses adsorption of the natural estrogen estrone to microfiltration hollow fibre membrane from aqueous phase. The partitioning of estrone between membrane and aqueous phase at equilibrium, the concept of membrane retention of estrone as a result of adsorption, adsorption kinetics, and the potential application of membrane adsorption have been assessed through batch adsorption and dead-end filtration studies using solutions containing trace estrone. The results show that adsorption could result in significant accumulation of estrone on membrane surfaces. The partitioning of estrone between membranes and aqueous phase can be characterized by the Freundlich equation. The microfiltration membrane could exhibit high retention to estrone due to adsorption but the retention decreases with increase in amount of estrone accumulated on the membrane surface. The results of this study have important implications, especially in drinking water applications. Contaminants such as natural and synthetic hormones may accumulate on membranes during treatment and desorb during backwash or membrane cleaning. Further studies are needed to address risk issues involved.