Fracture of a monolayer graphene is governed by the competition between bond breaking and bond rotation at a crack tip. Using atomistic reaction pathway calculations, we identify a kinetically favorable fracture path that features an alternating sequence of bond rotation and bond breaking. Our results suggest that the mechanical cracking can create fracture edges with nanoscale morphologies due to the non-uniform bond deformation and rupture induced by the localized high stresses near the crack tip. Such fractured edges may provide a structural basis of tailoring the electronic properties of graphene either intrinsically or by further edge functionalization. (C) 2010 Published by Elsevier B. V.