A disposable diaper comprising an absorbent core that is encased between a liquid pervious topsheet and a liquid impervious backsheet, elasticized leg openings, and a fastening device for securing the diaper on a wearer. The fastening device comprises a first member having a plurality of fiber elements and a second member having a plurality of engaging elements that are mechanically engageable with the fiber elements of the first member. The engaging elements are disposed and manufactured so as to provide a fastening device that is capable of resisting the peel forces and shear stress that are encountered during use and that is comfortable and skin friendly for the wearer. Each of the engaging elements thus preferably comprises a stem and an enlarged head positioned on one end of the stem; the head having a smooth, generally convex top surface that provides a skin friendly second member and a bottom surface that extends radially outwardly from the stem to engage the fiber elements of the first member. The fiber elements of the first member and the engaging elements of the second member are configured to maximize peel resistance such that the fastening device has a fiber overhang ratio of at least about 2:1 and a height ratio of at least about 5:1.