The mechanical properties of biomaterials need to be known and standardised before design, construction and testing of processing and handling machinery can be undertaken. Since experiments in the past have proved the viscoelastic nature of biomaterials, it is necessary to characterize them in order to ascertain their response to handling and processing. For engineering materials, the application of the theory of viscoelasticity is now quite well known; but this is not the case for biomaterials. In the characterization of biomaterials it will be necessary to modify the basic theory in the context of the bio-effects. The theoretical considerations are discussed in this study. The various bio-engineering terms are defined and viscoelastic representation with particular emphasis on bio-creep and relaxation is described. An attempt is made to show analogy with the mechanical models and their generalization. Barreleffect for viscoelastic materials of bio-origin is outlined. The shift-factors and their significance as a materialproperty are also included.