The　La0.8Sr0.2MnO3/ZnO　heterostructures　with　different　thicknesses　of　ZnO　films　are　fabricated　by　using　RF　magnetron　sputtering　technique.　The　heterojunctions　exhibit　excellent　rectifying　properties　at　300　K.　At　low　temperatures　the　temperature　dependent　junction　resistance　exhibits　a　metal-insulator　transition　like　behavior.　A　magnetic　field　strongly　impacts　on　electrical　characteristics　of　La0.8Sr0.2MnO3/ZnO　p-n　junctions,　i.e.,　depressing　the　junction　resistance　greatly　and　driving　the　metal-insulator　transition　temperature　(T-MI)　towards　higher　temperatures.　Large　magnetoresistance　is　observed　below　T-MI,　and　it　increases　with　increasing　magnetic　field　and　almost　saturates　at　5　T,　i.e.,　above　-90%　at　100　K　and　5　T.　(C)　2010　Elsevier　B.V.　All　rights　reserved.