The wool scale present on the fiber surface gives rise to certain unwanted effects in textile wet processing. The effects, for example, include felting and poor wettability. In the past, the removal of scale was done either by surface modification through physical/chemical degradation of scale or by deposition of a polymer on the scale. In modern treatment, combination of both methods is usually carried out. Since the deposition of a polymer on the fiber surface depends much on the surface characteristics of the fiber, therefore, the required surface property of modified fiber is an important factor for polymer application. On the other hand, the surface modification methods may also result in improved wettability on the surface of fiber. The present study investigated the surface physico-chemical properties of wool fiber subjected to different surface modification treatments. In this study, Soxhlet extracted (dichloromethane extracted) wool fibers (21 mu m diameter) were modified by low temperature treatment using different plasma gases, namely oxygen, nitrogen, and 25% hydrogen and 75% nitrogen gas mixture. The study of surface physico-chemical properties included contact angle measurements with different liquids, and determination of critical surface tension and surface free energy. Experimental results showed that these properties were improved after surface modification treatments and the results were quantitatively discussed.