The characteristic properties of molecular chains are their length, anisotropy and mobility. Although the macroscopic (mechanical) properties of polymers basically reflect these molecular characteristics, it is not always easy to identify the response of an individual molecule to stress. Much of the scientific work of Ward has been devoted to this problem and it is for this reason that some specific aspects of the stress transfer through chain molecules will be elaborated here. Thus, the representation of molecular anisotropy through aggregate models, the extreme situations of stress transfer through tie-molecules in semicrystalline fibres (shear stresses up to 3.5 GPa) and in elongational flow will be discussed. Recent results of stress transfer across interfaces in cracked homopolymers and in blends will be reviewed.