Ourdays in manufacture of technical fabrics materials from fiber glasses are widely used. By manufacture of technical fabrics from fiber glasses, it is necessary to observe strictly the chosen technological parameters, because for fiber glasses is high enough durability and stiffness, but very low elongation and factor of friction, that leads to fragility of fibers. In the work there was investigated influence of sizing process to such E glass yarn properties as strength, extension at break, surface smoothness, coefficient of friction and imbalance. Influence of sizing process to yarn breakage in weaving was examined. During the work it was established, that sizing process does not increase durability of glass fibers. The main result of sizing process of glass threads – increasing of the durability to friction and removal of an external pressure.