Current　distributions　in　a　proton　exchange　membrane　fuel　cell　(PEMFC)　with　interdigitated　and　serpentine　flow　fields　under　various　operating　conditions　are　measured　and　compared.　The　measurement　results　show　that　current　distributions　in　PEMFC　with　interdigitated　flow　fields　are　more　uniform　than　those　observed　in　PEMFC　with　serpentine　How　fields　at　low　reactant　gas　flow　rates.　Current　distributions　in　PEMFC　with　interdigitated　flow　fields　are　rather　uniform　under　any　operating　conditions,　even　with　very　low　gas　flow　rates,　dry　gas　feeding　or　over-humidification　of　reactant　gases.　Measurement　results　also　show　that　current　distributions　for　both　interdigitated　and　serpentine　flow　fields　are　significantly　affected　by　reactant　gas　humidification,　but　their　characteristics　are　different　under　Various　humidification　conditions,　and　the　results　show　that　interdigitated　flow　fields　have　stronger　water　removal　capability　than　serpentine　flow　fields.　The　optimum　reactant　gas　humidification　temperature　for　interdigitated　flow　fields　is　higher　than　that　for　serpentine　flow　fields.　The　performance　for　interdigitated　flow　fields　is　better　with　over-humidification　of　reactant　gases　but　it　is　lower　when　air　is　city　or　insufficiently　humidified　than　that　for　serpentine　flow　fields.　(C)　2009　Published　by　Elsevier　B.V.