The different steps for manufacturing a microchannel reactor for the PROX reaction are discussed. Transient Liquid Phase bonding (TLP) using a Ni-B-Si amorphous melt spun is used for joining micromilled Al-alloyed ferritic stainless steel plates followed by recrystallization at 1200°C for 5h. A CuOx-CeO2 catalyst synthesized by the coprecipitation method was washcoated on the microchannel block resulting in a homogenous 20-30μm thick layer. The catalytic activity for CO-PROX reaction is similar in both the powder catalyst and the microchannel coated reactor but the selectivity is higher in the microchannel reactor. © 2010 Elsevier B.V. ; Financial support by PETROBRAS and the Spanish Ministry of Science and Innovation through (MAT-2006-12386-C05) and (ENE-2009-14522-C05-01). O.H. Laguna and F.J. Echave thank to the same Ministry for their FPI fellowships (BES-2007-14409) and (BES-2007-15297) respectively. Junta de Andalucía (P06-TEP-08480) is gratefully acknowledged, also by S.A. Cruz for her fellowship. This work has been co-financed by FEDER funds from European Union. TEKNIKER is acknowledged for the mechanical construction.