NOVELTY - Producing a diesel fuel, involves: mixing a biocomponent feed portion having an oxygen content of at least 8 wt.% with a mineral feed portion to form a combined feedstock, the biocomponent feed portion is at least 5 wt.% of the combined feedstock; and contacting the combined feedstock with an isomerization/dewaxing catalyst comprising (i) a molecular sieve selected from ZSM-23 and/or ZSM-48, and (ii) a hydrogenation metal, under isomerization/dewaxing conditions including a temperature of at least 350 degrees C.    USE - For producing a diesel fuel (claimed).    ADVANTAGE - The method removes the oxygen content of 99% of the combined feed and produces an isomerized/dewaxed product having a cloud point of less than or equal to -20 degrees C; and produces diesel fuel products with improved cold flow properties and with increased cetane.    DETAILED DESCRIPTION - Producing a diesel fuel, involves: mixing a biocomponent feed portion having an oxygen content of at least 8 wt.% with a mineral feed portion to form a combined feedstock, the combined feedstock having a sulfur content of less than 50 weight parts per million (wppm) and a nitrogen content of less than 20 wppm, the biocomponent feed portion is at least 5 wt.% of the combined feedstock; and contacting the combined feedstock with an isomerization/dewaxing catalyst comprising (i) a molecular sieve selected from Beta, USY, ZSM-5, ZSM-35, ZSM-23 and/or ZSM-48 (preferably ZSM-23 and/or ZSM-48) and having a silica to alumina ratio of 90:1 or less, and (ii) a hydrogenation metal, under isomerization/dewaxing conditions including a temperature of at least 350 degrees C, to remove the oxygen content of 99% of the combined feed and to produce an isomerized/dewaxed product having a cloud point of less than or equal to -20 degrees C, where the hydrogenation metal is Group VIII hydrogenation metal (at least 2 wt.%) selected from nickel (Ni) and/or cobalt (Co) plus Group VIB hydrogenation metal (at least 10 wt.%) selected from molybdenum (Mo) and/or tungsten (W).