A disposable diaper comprising an absorbent unit has been patented. The diaper features a liquid-pervious topsheet and a liquid-impervious backsheet surrounding a liquid-absorbent core. The absorbent unit contains a longitudinal centerline, a front and rear waist region and a crotch region. A removable body waste disposable sheet is bonded to the crotch region. The unit is provided along transversely opposite side edge regions with a pair of pleats extending in a longitudinal direction. Each pair of pleats has a Z-shaped cross section, defined by a lower portion folded toward the longitudinal centerline and has an upper portion folded outward. The lower portion is folded and the disposable sheet is bonded along transversely opposite side edges, extending in the longitudinal direction to the upper portions of the pleats so that the body waste disposal sheet is separated from the absorbent unit when the pleats are pulled in opposite directions.