In accordance with the present disclosure a directionally biased staple is provided for use in all types of surgical staplers having anvil structure against which the staple is formed. The directionally biased staple may be constructed in a wide variety of cross-sectional configurations including rectangular, elliptical, trapezoidal, etc. All of the configurations are distinguished by having a bending region requiring more force to twist or malform the staple than is required to properly form the staple. Preferably, these staples have Moment of Inertia Ratios on the order of between about 1.1 to about 3.0. The staple preferably corresponds in other respects to conventional formed staples, i.e. having at least a pair of leg members interconnected by a crown portion wherein the leg members are formed by direct contact with the anvil. An anvil assembly is also provided for minimizing the malformation of staples.