The invention relates to a disposable incontinence diaper (2), with a main part (4) comprising a front region (12), a rear region (16) with rear lateral longitudinal edges (18), and rear side portions (22) attached on both sides to the rear region (16), whereas no side portions (22) are attached to the front region (14), and instead front lateral longitudinal edges (14) of the main part (4) form a free-ending longitudinal edge of the diaper, wherein the rear side portions (22) can each be placed in a circumferential direction around the body of a user, in order to apply and close the disposable incontinence diaper (2) on the user, and can be brought into an overlapping arrangement with an outer face of the front region (12) at which they can then be affixed releasably via the respective closure means (28), wherein the rear side portions (22) have an extent Q in the transverse direction (10) in the state when spread out flat but not stretched, wherein the rear side portions (22) are elastically extensible within this extent Q in the transverse direction (10) and for this purpose have an elastic or elasticated region (42) extended in the transverse direction (10) and in the longitudinal direction (8), wherein this extent Q in the transverse direction (10) comprises a proximal portion (38), adjoining the rear lateral longitudinal edge (18), and a free-ending distal portion (40), and wherein the proximal portion (38), starting from the rear lateral longitudinal edge (18), extends in the transverse direction (10) by a length that is 65% of the extent Q of a rear side portion (22), characterized in that the respective elastic or elasticated region (42) of the rear side portions (22) is arranged completely within the proximal portion (38) and reaches the assigned rear lateral longitudinal edge (18) or is at a distance of at most 30 mm from the rear lateral longitudinal edge (18) in the transverse direction (10), and in that the respective rear side portions (22) are substa
