Selective carbamoylation of aniline by dimethyl carbonate has been performed under continuous flow using a microreactor having 10 mu m microchannels and 4 ml of total volume. Nanoparticulated ceria and gold nanoparticles supported on nanoparticulated ceria that have proved to be highly selective in batch reactions were tested as catalysts. The catalyst coating was deposited as thin film on the stainless steel microreactor plate that was previously activated by heating at 700 degrees C for 2 h. It was observed that at 120 degrees C and 5 bar pressure, both catalysts were stable over long times on stream reaching maximum conversions about 35%. (C) 2010 Elsevier B.V. All rights reserved.