Using　a　specially　designed　current　distribution　measurement　gasket　in　anode　and　thin　thermocouples　between　the　catalyst　layer　and　gas　diffusion　layer　(GDL)　in　cathode,　in-plane　current　and　temperature　distributions　in　a　proton　exchange　membrane　fuel　cell　(PEMFC)　have　been　simultaneously　measured.　Such　simultaneous　measurements　are　realized　in　a　commercially　available　experimental　PEMFC.　Experiments　have　been　conducted　under　different　air　flow　rates,　different　hydrogen　flow　rates　and　different　operating　voltages,　and　measurement　results　show　that　there　is　a　very　good　correlation　between　local　temperature　rise　and　local　current　density.　Such　correlations　can　be　explained　and　agree　well　with　basic　thermodynamic　analysis.　Measurement　results　also　show　that　significant　difference　exists　between　the　temperatures　at　cathode　catalyst　layer/GDL　interface　and　that　in　the　center　of　cathode　endplate,　which　is　often　taken　as　the　cell　operating　temperature.　Compared　with　separate　measurement　of　local　current　density　or　temperature,　simultaneous　measurements　of　both　can　reveal　additional　information　on　reaction　irreversibility　and　various　transport　phenomena　in　fuel　cells.　(C)　2009　Elsevier　B.V.　All　rights　reserved.