A container (1) for fluids, in particular fluids containing gas, comprises an outer casing (2) of flexible, pressure resistant material, at least a gas and/or fluid tight inner casing (3) of flexible material lying inside the outer casing and being separated therefrom, and at least a filling connection (4) for filling the inner casing. As a result, the container (1) is collapsible so that filling the container may take place from the collapsed condition and filling is therefore possible without pressure difference while the fluid does not enter an empty space. The egress of gas from the fluid is substantially reduced thereby. When fluid is discharged from the container (1), the volume of the container can also decrease by collapsing so that also during use of the fluid gas is prevented from egressing. Consequently, the quality of the fluid is maintained, both during filling of the inner casing with fluid and during discharge of fluid from the inner casing. When the container (1) is completely empty, it is collapsible in a flat manner and occupies only little room, which is very favorable for transport and storage.