Hydraulic tank for an industrial truck, comprising: - a tank lower part comprising a base and a side wall and produced in one piece, - a tank cover which is connected to an upper edge of the side wall, is produced in one piece and defines at least one hydraulic-medium receiving chamber together with the base and the side wall, - at least one hydraulic-medium intake pipe extending from a hydraulic-medium intake connector of the tank cover, preferably into a lower region of the hydraulic-medium receiving chamber, - at least one hydraulic-medium return pipe extending from a hydraulic-medium return connector of the tank cover, preferably into a lower region of the hydraulic-medium receiving chamber, the hydraulic-medium intake pipe and the hydraulic-medium return pipe, together with the tank cover, forming a tank upper part which is assembled as a modular unit together with the tank lower part to form the hydraulic tank, characterised in that a front and a rear wall portion are connected by at least one intermediate element (94a, 94b, 94c) which extends between said wall portions and is preferably in the form of a partition which is open or comprises at least one hydraulic-medium passage, which intermediate element acts as a baffle and/or as tank reinforcement, each intermediate element (94a, 94b, 94c) on the front and the rear wall portion engages in an interlocking manner with a holding structure (78a and 78b; 80a and 80b; 82a and 82b) of the front and rear wall portion, which holding structure is produced, preferably in an injection-moulding process, in one piece together with the side wall, it being possible to transfer both tensile forces and compressive forces between the front and the rear wall portion by means of the intermediate element and the interlocking engagement with the holding structures (78a, 78b; 80a, 80b; 82a, 82b), and the holding structures of the front and the rear wall portion being formed as holding connecting pieces (78a, 78b; 80a, 80b; 82a, 82b) on the inside of the wall and extending in the direction of a vertical axis of the hydraulic tank, each of which connecting pieces comprises a holding aperture (96a; 96b) which extends in the direction of the vertical axis and, proceeding from a guide-through slot, widens in the transverse direction in order to engage with a holding edge (100a; 100b), formed in a substantially complementary manner, of the intermediate element (94a, 94b, 94c) in order to form the interlocking engagement. - a tank lower part comprising a base and a side wall and produced in one piece, - a tank cover which is connected to an upper edge of the side wall, is produced in one piece and defines at least one hydraulic-medium receiving chamber together with the base and the side wall, - at least one hydraulic-medium intake pipe extending from a hydraulic-medium intake connector of the tank cover, preferably into a lower region of the hydraulic-medium receiving chamber, - at least one hydraulic-medium return pipe extending from a hydraulic-medium return connector of the tank cover, preferably into a lower region of the hydraulic-medium receiving chamber, the hydraulic-medium intake pipe and the hydraulic-medium return pipe, together with the tank cover, forming a tank upper part which is assembled as a modular unit together with the tank lower part to form the hydraulic tank,