A plastic pallet in which a plurality of beam assemblies are positioned beneath the plastic main body of the pallet to discourage warpage and failure of the pallet, especially in racked, loaded storage situations. The plastic structure of the pallet includes a planar platform section defining an upwardly facing load receiving surface and a plurality of legs extending downwardly from the platform section to define tunnels therebetween for receipt of the forks of a forklift truck. The beam structures extend in parallel fashion beneath the plastic structure. Each beam structure includes a central upstanding spine portion received in downwardly opening grooves defined in the bottoms of aligned legs, and a base portion which extends beneath the bottoms of the legs to provide a base on which each pallet may rest. Each beam structure is formed of a central tubular steel beam encapsulated by upper and lower plastic sheets which are fused together to totally enclose the steel beam and to form the base portion of the beam structure.