The effects of the stack operating temperature, methanol solution feeding rate, and concentration of methanol solution on two-cell, three-cell, and four-cell micro-direct methanol fuel cell stacks were examined using electrochemical impedance spectroscopy and cyclic voltammetry. In addition to the transient techniques, both VI/PI polarization curves were obtained. Corresponding single-cell tests were conducted and used as basis/reference data for comparisons with previous studies or with the present stack results. The micro-direct methanol fuel cell stack used in the study was operated actively at the anode and passively (i.e., air breathing) at the cathode where a serpentine-type channel and novel/innovative perforated dendrite-type channel with a 80 degrees dendrite angle flow configuration were used for both the anode and cathode. Relevant data were measured, presented, and discussed under the aforesaid operating conditions. Moreover, the results were compared with those of earlier works and found to be in good agreement. Copyright (c) 2016 John Wiley & Sons, Ltd.