In the present work the effect of three different anode and cathode flow field designs (single serpentine (SFF), multi-serpentine (MSFF) and an original design mixed parallel and serpentine (MFF)) on the performance of a DMFC, was investigated experimentally. The studies were conducted in an "in-house" developed DMFC with 25 cm(2) of active membrane area, working near ambient pressure, using two values of methanol concentration (0.75 M and 2 M), of fuel cell temperature (20 degrees C and 60 degrees C), of methanol flow rate and of air flow rate. With respect to the anode flow field design it was found that for the two values of methanol flow rate tested, the lower value of fuel cell temperature and lower value of methanol concentration, the use of MFF has a positive effect on cell voltage and power. For the cathode flow field design, for the two values of air flow rate tested, for the lower value of fuel cell temperature and lower value of methanol concentration the use of MSFF leads to a better performance. For the higher value of methanol concentration tested, a very important condition for portable applications, the use of MSFF or MFF as anode flow field design and MSFF or SFF as cathode flow field design leads to an enhanced fuel cell performance. Most of the reported experiments were conducted close to room temperature, providing information and results that can be used when designing a portable DMFC, where less severe operating conditions are required (ambient temperature and ambient pressure). (C) 2009 Elsevier B. V. All rights reserved.