A disposable absorbent undergarment such as a diaper includes short pants and a liquid-absorbent pad attached to an inner surface of the short pants. The short pants has a front waist section, a rear waist section, a crotch section interposed therebetween, a waist-opening and a pair of leg-openings. The crotch section, the waist-opening and the leg-openings are elastically stretchable. A circumferential region defined by portions of the front and rear waist sections between the waist opening and upper ends of the leg-openings is also elastically stretchable.