A method for preparing membrane electrode assemblies (MEA) for direct methanol fuel cells (DMFCs) by a layer-upon-layer fabrication onto a porous substrate is presented. This preparation technique is based on a single method for the fabrication of the whole MEA, e.g., spraying one functional layer onto the other, and therefore simplifies its preparation considerably. It also permits new fuel cell designs with in-plane serial connection of single cells by appropriate fabrication procedures. It is therefore especially suited for low power microfuel cells operated at ambient conditions. This method offers high flexibility in the choice of cell geometry as well as superior control of the structural parameters of the layer. Parameters like layer thickness or composition, catalyst and ionomer loadings can easily be varied and adapted to the specific needs of the ionomer and catalysts used. Here process parameters enabling such a layer-upon-layer MEA preparation have been developed successfully. Initial results with single cells prepared with the new technique are presented and compared with conventionally fabricated MEAs. Power densities of at a cell voltage of 0.4 V have been achieved with single cells at ambient conditions, 0.5 M MeOH solution, and self-breathing cathode. This result is promising since conventionally prepared MEAs with prefabricated membranes show similar power densities. A planar multicell configuration is proposed and issues concerning serial connection in this concept are discussed and future work proposed. © 2005 The Electrochemical Society. All rights reserved.