To prepare a diesel gas oil compsn. which stably exhibits excellent low-temp. fluidity even in the case of a small kerosene fraction content by adding a surfactant fluidity improver to a diesel gas oil having particular properties.

This diesel gas oil compsn. comprises a diesel gas oil satisfying the formula Y≤-0.0051X2+0.50 (wherein Y represents the percentage precipitation of wax (wt.%/°C); and X represents the cloud point (°C)) and a surfactant fluidity improver added thereto. The amount of the surfactant fluidity improver added is pref. 20 to 2000mg/L. Pref. surfactant fluidity improvers usable herein include an alkenylsuccinic amide or alkenylsuccinic imide compd., an ester of a nitrogen-contg. compd. having a hydroxyl group with a straight-chain satd. fatty acid, and a polymer of this compd. with at least one member selected from the group consisting of an olefin, an ethylenically unsatd. alkyl carbonate, and a satd. fatty acid vinyl ester.