A disposable diaper in which the main absorbent pad is a fluff batt having a specially selected localized area of increased density to improve the effective fluid absorbing capabilities of the diaper when worn, and to minimize waist leakage problems. The localized area of increased density is longitudinally centered in the back panel at the upper rear section of the diaper as worn, and extends from the waist of the diaper to the approximate transverse midpoint of the diaper. This densified area is also spaced inwardly from the side edges of the diaper to leave sections of undensified fluff along each side.