Ethyl acetate removal from an air stream was carried out by using a flat composite membrane bioreactor. The composite membrane consisted of a dense polydimethylsiloxane top layer with an average thickness of 0.3 mu m supported in a porous polyacrylonitrile layer (50 mu m). The membrane bioreactor (MBR) was operated during 3 months, and a maximum elimination capacity of 225 g m(-3) h(-1) at an empty bed residence time of 60 s was observed. Removal efficiencies higher than 95% were obtained for inlet loads lower than 200 g m(-3) h(-1) and empty bed residence times as short as 15 s. The estimated yield coefficient, determined from the carbon dioxide production, resulted in 0.82 g dry biomass synthesized per gram of ethyl acetate degraded. No data of ethyl acetate treatment in MBR have been found in the literature, but the results illustrate that membrane bioreactors can potentially be a good option for its treatment. (C) 2011 Published by Elsevier Ltd.