A dual piston accumulator, in particular for a hydrostatic hybrid drive system for vehicles, replaces a high pressure hydro accumulator and a low pressure hydro accumulator. Inside a single accumulator housing (2) extending in the axial direction in a single piece over a high pressure part (4) and a low pressure part (6), an accumulator piston (8, 10) defines a high pressure-sided fluid chamber (16) and a low pressure-sided fluid chamber (18). Both chambers border an intermediate piece (12) separating the high pressure side (4) from the low pressure side (6). A common piston rod (14) extends through the intermediate piece for both accumulator pistons (8, 10). The wall width of the housing (2) corresponding to the high pressure part (4) is greater than the opposite reduced wall width corresponding to the low pressure part (6).