Sliding friction between orthogonally crossed silica monofilaments was measured as a function of applied normal load using an electronic microbalance. In the adhesion model of friction, the friction is interpreted in terms of shearing the junction. With the assumption that the ploughing term of friction can be ignored, the shear strength can simply be represented by tau = F/A where F is frictional force, A is the real area of contact, and tau is the interfacial shear strength. Assuming a single point contact between two fibres, the estimation of the real area of contact was made from Hertzian analysis by taking the normal load as a sum of the applied force and independently determined adhesional force. The results showed that the shear strength of freshly drawn silica fibre increases linearly with the contact pressure.