Polyester fibers (PET) are greatly used in textiles but depend on fossil fuel resources. Poly-(lactic acid) (PLA) is an aliphatic polyester that can be derived from 100% renewable resources. The load-extension plot of a polylactide fiber seems to be especially compatible with that of wool. Consequently polyester/wool 55/45 and polylactide/wool 55/45 yarns were spun using the Sirospun process and plain and twill woven fabrics were industrially produced. Washed and heat set fabrics were subjected to a conventional process of dyeing and decatizing. Fabrics were gradually worn by abrasion using a Martindale wear and abrasion tester.; Using the bursting strength test, the viscoelastic behavior of the fabrics when multidirectional extended was simulated and modeled using a modified non-linear Maxwell model. The three steps of fiber decrimping and orientation, fiber stretching and maximum yield and breaking were analyzed. PET/wool fabrics show a more linear behavior than PLA/wool ones and the influence of weave, finishing and wearing on the viscoelastic behavior of PLA/wool fabrics were highly relevant when compared with that on PET/wool ones. It seems that when blended with PET, wool develops its felting effect during finishing and wearing, while when blended with PLA, the felting effect of wool is hardly developed due to the lower resistance of PLA to hydrolysis and its lower thermal stability. PLA fiber properties need to be improved probably through the development of new L-D lactide (PLDLA) copolymers of different ratios between components and molecular weights to reach the optimal desirable properties for the fiber.