A simple disposable absorbent article including a chassis and an absorbent assembly. The chassis includes a water-impermeable sheet folded laterally inward at both of its side edges to form opposing side flaps. Each side flap is attached to the interior surface of the chassis adjacent to its end edges. Each side flap has a longitudinally extending elastic gathering member attached adjacent to its proximal edge. The absorbent assembly is smaller in width and in length than the chassis. The side edges and end edges of the absorbent assembly may be disposed proximally relative to the respective side edges and end edges of the chassis. The absorbent assembly includes an absorbent core that may contain superabsorbent particles, which may be contained inside pockets. The chassis may be extensible. The absorbent assembly may be attached in a cruciform pattern to the chassis to allow portions of the chassis to extend laterally.