Abstract: A boot with a heel-back fastening mechanism has a split heel-back through which the foot of the user is inserted into the foot receiving cavity of the boot shell. The boot includes a boot shell having a heel cup secured to a sole assembly. The boot shell has a split heel-back that forms a boot shell left side and a boot shell right side. The heel-back fastening mechanism includes a flexible heel center member, a plurality of heel securing straps, and a plurality of heel securing grommets. The flexible heel center member extends away from the heel cup and is sealingly connected between the left and right sides of the boot shell. The plurality of heel securing straps each has an end secured to one of the boot shell sides. Each of the heel securing grommets is secured through a side of the boot shell opposite the point of attachment for each end of the plurality of heel straps. Each of the plurality of heel securing straps includes first and second companionate sections of hook and pile fastener material.